Tri-, Tetra-, Penta-, and polypeptides and their therapeutic use as an antidepressant agent

ABSTRACT

The present invention discloses novel peptides utilized to treat patients suffering from depression. These novel peptides are modifications of the tripeptide hormone MIF, including modification of amino terminus residues, carboxyl terminus residues and internal residues, including addition and substitution of amino acid residues and modification of the peptide bonds and functional side groups of respective amino acid residues. The tri-, tetra-, penta-, peptides and polypeptides of the present invention may be utilized alone or in combination to treat patients suffering from depression.

1. CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 08/432,651 filed on May 2, 1995, now U.S. Pat. No. 5,767,083; which is a continuation-in-part of U.S. patent application Ser. No. 08/238,089 filed on May 4, 1994, now U.S. Pat. No. 5,589,460.

2. INTRODUCTION

Heterogeneous unipolar and bipolar depression is a common psychiatric disorder most likely mediated by neurochemical changes in the central nervous system. Administration of antidepressant drugs for treatment of unipolar depression has gained wide acceptance in the medical community over the past several decades. The present invention discloses novel peptides and their use as therapeutic agents in treating patients suffering from depression.

3. BACKGROUND OF THE INVENTION

Endogenous depression is thought to be a genetically determined biochemical disorder which results in an inability to deal with stress. This form of depression is oftentimes classified as unipolar depression, which is subclassified into retarded depression and agitated depression. Retarded depression is characterized by psychomotor retardation, where the subject does not interact with the surrounding environment to any extent. Agitated depression is, on the other hand, characterized by increased unproductive activity such as pacing, hand wringing, etc.

Unipolar depression is most likely a disorder resulting from a number of heterogeneous changes in the brain. One school of thought subscribes to the catecholamine theory: that endogenous depression is caused by a reduction in norepinephrine concentration within the vicinity of adrenergic receptor sites in the brain. Another possibility is that endogenous depression is caused by an absolute or relative deficiency in indoleamine, specifically 5-hydroxytryptamine, at receptor sites in the brain.

The course of treatment for endogenous depression is electroconvulsive therapy or drug therapy. The drugs administered for therapeutic treatment of depression include (1) tricyclic antidepressants, (2) monoamine oxidase (MAO) inhibitors, and (3) second-generation antidepressants.

Tricyclic drugs have been the drug of first choice in treating endogenous depression for over three decades. However, these drugs have limited efficacy in that two-thirds of patients receiving tricyclic drugs do not respond favorably. The side effects of the tricyclics are numerous, including cholinergic blockage, cardiac complications, allergic reactions, dry mouth, constipation, blurred vision and tachycardia. The tricyclic drugs are characterized structurally by a three-ringed nucleus. The tricyclic antidepressants include imipramine, desipramine, amitriptyline, nortriptyline, protriptyline, doxepin and trimipramine. These tricyclic structures are metabolized through the mixed-function oxidase system. These metabolites are the pharmacologically active compounds.

The MAO inhibitors have been available for treatment of depression since the 1950's. These compounds are classified either as hydrazides, exemplified by a C-N-N moiety (e.g., pheneizine and isocarboxazid) or a nonhydrazide (e.g., tranylcypromine). These drugs have not gained wide acceptance due to serious side effects.

The so called second-generation drugs are a group of new drugs which include amoxapine, maprotiline, fluoxetine, tirazodone and bupropion. Most of these drugs seem to act in the same fashion as the tricyclic drugs.

Antidepressant drugs must cross the blood-brain barrier in pharmacologically effective concentrations. The capillaries of the central nervous system, unlike capillary beds feeding other organs, possess tight junctions with cerebral endothelial cells. Therefore, the human blood-brain barrier is a lipid barrier without pores. Any potential antidepressant drug must be designed such that the compound is able to traverse the blood-brain barrier. Compounds with low lipid solubility as well as many ionized compounds are unable to exit the circulation for entry into the extracellular fluid of the brain. Water soluble compounds will traverse the blood-brain barrier only if a specific membrane transport system exists. In contrast, lipid soluble drugs, in effect, are not hampered by the blood-brain barrier.

The tripeptide MIF, otherwise known as melanocyte stimulating inhibitory factor, which is represented by the chemical formula of prolyl-leucyl-glycinamide or Pro-Leu-Gly-NH₂, has been shown to produce numerous non-endocrine effects on the brain. The MIF tripeptide has also been shown to be active in a number of animal models for depression.

MIF was initially isolated and characterized from bovine hypothalmic extracts (Nair, et al., 1971, Biochem. Biohys. Res. Comm. 43(6): 1376-1381) and rat hypothalmic extracts (Celis, et al., 1971, Proc. Natl. Acad. Sci. USA 68(7): 1428-1433). MIF activity was attributed to inhibiting release of melanocyte stimulating hormone, a pituitary hormone known to stimulate melanin production. Neither disclosure suggests or discloses any potential antidepressant activity for MIF.

U.S. Pat. No. 3,708,593 (issued to N. P. Plotnikoff on Jan. 2, 1973) teaches that MIF exhibits antidepressant activity in mice, as shown by a modified Dopa test (Everett, et al., 1966, Proc. 1^(st) Int. Sym. Anti-depressant Drugs, p. 164).

U.S. Pat. No. 3,795,738 (issued to N. P. Plotnikoff on Mar. 5, 1974) teaches that MIF, alone or in combination with other known drugs, exhibits increased activity against Parkinson's disease.

U.S. Pat. No. 3,931,184 (issued to C. G. Lex on Jan. 6, 1976) teaches isolation of medicinally pure MIF. A MIF hemihydrate is dissolved in methanol, followed by the addition of diethyl ether, resulting in a white crystalline precipitate of MIF. This pure MIF is collected, washed with ether and dried under vacuum prior to use.

U.S. Pat. No. 4,278,595 (issued to J. H. Cort on Jul. 14, 1981) teaches that practical use of MIF has been hindered because MIF is rapidly metabolized subsequent to administration. Due to this relatively short half-life of MIF, it has been necessary to administer large quantities of MIF intravenously over prolonged periods to obtain efficacious concentrations. Cort teaches a MIF analog characterized by replacement of Leu with its D-isomer, optionally replacing Pro with pGlu, and optionally alkylating the terminal amide group of Gly-NH₂ to produce a MIF analog. Such an analog may possess similar antidepressant activity as MIF and enhanced stability. Cort teaches a tripeptide having the formula X-D-Leu-NH₂ -CH₂ -CONR¹ R², where X is Pro or pGlu and each of R¹ and R² independently is H or a lower alkyl, especially methyl or ethyl.

Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:112)) is a brain derived peptide shown to affect passive avoidance in rats (Hayashi, et al., 1983, Brain Res. Bull. 11: 659-662). Various analogs to Tyr-MIF-1 (i.e., substitutions for the Tyr residue, resulting in Ala-MIF-1, Leu-MIF-1 or Phe-MIF-1) were tested for a possible affect on behavioral and motor activities (Hayashi, et al., 1984, Pharmacology Biochemistry & Behavior 21: 809-812). Ala-MIF-1 and Phe-MIF-1, but not Leu-MIF-1, affected passive avoidance behavior in rats. None of these peptides were shown to affect motor behavior.

Kastin, et al. (1984, Pharmacology Biochemistry & Behavior 21: 767-771) discloses that MIF-1 and Tyr-MIF-1 are active as antidepressants. The degree of activity was measured by the water wheel test, a modification of the Porsolt swim test.

Kastin, et al. (1985, Pharmacology Biochemistry & Behavior 23: 1045-1049) determined that Tyr-MIF-1 and several Tyr-MIF-1 analogs possess antiopiate activity. Along with Tyr-MIF-1, Phe-MIF-1 was active in inhibiting the analgesic effect of morphine in rats.

Banks, et al. (1986, Am. J. Physiol. 251 [Endocrine Metabolism 14]: E477-E482) identifies the carrier-mediated transport system responsible for delivery of Tyr-MIF-1 to the extracellular brain fluid from the circulatory system.

It would be extremely useful to design and generate modified small peptides for treating patients suffering from depression which possess pharmacological activity subsequent to crossing the blood-brain barrier without inducing the side effects inherent in many of approved antidepressant drugs available today.

4. SUMMARY OF THE INVENTION

The present invention discloses modified small peptides for use as antidepressant compounds. According to the invention, these novel peptides are utilized to treat patients suffering from depression. These modifications target amino terminus residues, carboxyl terminus residues and internal residues, including addition and substitution of amino acid residues and modification of the peptide bonds and functional side groups of respective amino acid residues as more fully described hereinbelow.

It is an object of the invention to provide peptides which have pharmacologic activity.

It is another object of the invention to provide peptides useful in treating patients exhibiting symptoms of depression.

It is a feature of the invention to synthesize and provide small peptides representing novel modifications, substitutions, additions and/or deletions to a MIF core structure which have anti-depressant activity.

It is an advantage of the invention to provide small peptides which may be administered at lower dosages than known anti-depressants so as to reduce potential deleterious side effects.

In one embodiment of the invention, the small peptides of the present invention are tripeptides characterized by formula (1):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -NR.sup.2 -CH.sub.2 -R        (1)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group Trp, Orn, Lys, Leu, D-Leu, Arg, D-Arg, or Ile; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycaibonyl group; R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino group or dimethyl or diethylamino group; and, R² represents a hydrogen atom or a lower alkyl group, preferably having 1 to 3 carbon atoms, with the proviso that where Pro¹ is Pro and AA¹ is Leu, then R¹ and R² cannot both be a hydrogen atom when R is a carbamyl group, since MIF is a known compound.

An embodiment of tripeptides of formula (1) disclosed for utilization in treating depression in patients is formula (1a):

    Pro.sup.1 -AA.sup.1 -Gly-NH.sub.2                          (1a)

wherein Pro¹ and AA¹ are as described above for formula (1). Preferred compositions of the tripeptides of formula (1a) include, but are not necessarily limited to, Pro-Trp-Gly-NH₂, Pro-Arg-Gly-NH₂, Pro-D-Argr-Gly-NH₂, Pro-Lys-Gly-NH₂, Pro-Orn-Gly-NH₂, and Pro-Ile-Gly-NH₂.

Another embodiment of tripeptides of formula (1) disclosed for utilization in treating depression in patients is formula (1b):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Gly-NH.sub.2                 (1b)

wherein Pro¹, AA¹ and R¹ are as described above for formula (1). Preferred compositions of the tripeptides of formula (1b) include, but are not necessarily limited to cis- or trans-4-OH-Pro-D-Arg-Gly-NH₂, cis- or trans-4-OH-Pro-Ile-Gly-NH₂, cis- or trans-4-OH-Pro-Arg-Gly-NH₂, cis- or trans-4-OH-Pro-Trp-Gly-NH₂, and cis- or trans-4-thio-Pro-Leu-Gly-NH₂.

A further embodiment of trirpeptides of formula (1) disclosed for utilization in treating depression in patients is formula (1c):

    Pro.sup.1 -AA.sup.1 -NR.sup.2 -CH.sub.2 -R                 (1c)

wherein Pro¹, AA¹, R and R² are as described above for formula (1), with the proviso that where Pro¹ is Pro and AA¹ is Leu, R² cannot be a hydrogen atom when R is either a carboxyl group or a hydroxyalkyl group, since these compounds, i.e., Pro-Leu-NHCH₂ -CO₂ H (or Pro-Leu-Gly) and Pro-Leu-NHCH₂ -CH₂ OH, do not form part of this invention, and with the further proviso that where Pro¹ is Pro and AA¹ is Trp, R² cannot be a hydrogen atom when R is a hydroxyalkyl group, since Pro-Trp-NHCH₂ -CH₂ OH is a known compound. Preferred compositions of the tripeptides of formula (1c) include, but are not necessarily limited to Pro-Leu-N(CH₃)CH₂ -CONH₂ (or Pro-Leu-Sar-NH₂) and Pro-Trp-NHCH₂ -CO₂ H (or Pro-Trp-Gly).

In yet a further embodiment, tripeptides of the present invention disclosed for utilization in treating depression in patients are represented by formula (2):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Ala-R                        (2)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Arg or D-Arg; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamoyl group, or an alkoxycarbonyl; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

An embodiment of the tripeptides of formula (2) disclosed for utilization in treating depression in patients is disclosed in formula (2a):

    Pro.sup.1 -AA.sup.1 -Ala-NH.sub.2                          (2a)

wherein Pro¹ and AA¹ are as described above for formula (2). Preferred compositions of the tripeptides of formula (2a) include, but are not necessarily limited to, Pro-Arg-Ala-NH₂ and Pro-D-Arg-Ala-NH₂.

In yet another embodiment, tripeptides of the present invention disclosed for utilization in treating depression in patients are represented by formula (3):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Tyr-R                        (3)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents the amino acid Orn; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group.

An embodiment of the tripeptides of formula (3) disclosed for utilization in treating depression in patients is formula (3a):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Tyr-NH.sub.2                 (3a)

where Pro¹, AA¹ and R¹ are as described for formula (3). Preferred compositions of the tripeptides of formula (3a) include, but are not necessarily limited to, Pro-Orn-Tyr-NH₂ and cis- or trans-4-OH-Pro-Orn-Tyr-NH₂.

The present invention also discloses tetrapeptides and use thereof in treating depression. One embodiment discloses C-terminus end enhanced tetrapeptide compositions represented by formula (4):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Gly-AA.sup.2 -R              (4)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents Ile, Leu, Arg, D-Arg or Trp; AA² represents an amino acid of the group of Trp or Tyr; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

An embodiment of tetrapeptides of formula (4) disclosed for utilization in treating depression in patients is formula (4a):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Gly-AA.sup.2 -NH.sub.2       (4a)

wherein Pro¹, AA¹, AA², and R¹ are as described for formula (4). Preferred compositions of the tetrapeptides of formula (4a) include, but are not necessarily limited to, cis- or trans-4-OH-Pro-Leu-Gly-Trrp-NH₂ (SEQ ID NO:1), cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:2), cis- or trans-4-OH-Pro-D-Arg-Gly-Trp-NH₂, 3,4-dehydro-Pro-D-Arg-Gly-Trp-NH₂ and 3,4-dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:62).

A further embodiment of tetrapeptides of formula (4) disclosed for utilization in treating depression in patients is formula (4b) is:

    Pro.sup.1 -AA.sup.1 -Gly-AA.sup.2 -NH.sub.2                (4b)

wherein Pro¹, AA¹ and AA² are as described for formula (4). Preferred compositions of the tetrapeptides of formula (4b) include, but are not necessarily limited to, Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:3), 3,4-dehydro-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:4), Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:5), Pro-Leu-Gly-Tyr-NH₂ (SEQ ID NO:6), Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:7), Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:8), Pro-D-Arg-Gly-Trp-NH₂, and Pro-Ile-Gly-Tyr-NH₂ (SEQ ID NO:9).

An additional embodiment of the tetrapeptides of the invention discloses N-terminus end enhanced tetrapeptide compositions represented by formula (5):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R (SEQ ID NO:113)(5)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Tip, Tyr or Phe; AA² represents an amino acid of the group of Leu, Ile, or Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

An embodiment of tetrapeptides of formula (5) disclosed for utilization in treating depression in patients is formula (5a):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-NH.sub.2 (SEQ ID NO:114)                                                   (5a)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (5), with the proviso that where Pro¹ is Pro, R¹ and R² cannot both be a hydrogen atom when AA¹ is Tyr and AA² is Trp, since this compound, i.e., Tyr-Pro-Trp-Gly-NH₂ (SEQ ID NO:54), is a known compound, and with the further proviso that where Pro¹ is Pro and AA² is Leu, R¹ and R² cannot both be a hydrogen atom when AA¹ is Phe or Tyr, since Phe-MIF-1 and Tyr-MIF-1 are known compounds. Preferred compositions of the tetrapeptides of formula (5a) include, but are not necessarily limited to, Trp-Pro-Leu-Gly-NH₂ (SEQ ID NO:10), Phe-Pro-Leu-Gly-NH₂ (SEQ ID NO:11), 4-F-Phe-Pro-Leu-Gly-NH₂ (SEQ ID NO:12), 4-Cl-Phe-Pro-Leu-Gly-NH₂ (SEQ ID NO:13), 4-F-Phe-Pro-Ile-Gly-NH₂ (SEQ ID NO:14), 4-F-Phe-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:15), 4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:16), Trp-Pro-Leu-Gly-NH₂ (SEQ ID NO:17), Trp-Pro-Ile-Gly-NH₂ (SEQ ID NO:18), Trp-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:19), Trp-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:20), and 4-Cl-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:60).

An embodiment of tetrapeptides of formula (5) disclosed for utilization in treating depression in patients is formula (5b):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R (SEQ ID NO:115)(5b)

wherein Pro¹, AA¹, AA², R¹, R² and R are as described for formula (5). Preferred compositions of the tetrapeptides of Iformula (5b) include, but are not solely limited to, additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a cis- or trans-4-OH- group; and additional optional modifications at AA², preferably Arg. A preferred peptide of formula (5b) is 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-1,2,3,4-Tetrahydroisoquinoline-3-carboxamide (SEQ NO:75).

The present invention further discloses pentapeptides and use thereof in treating depression. One embodiment of the pentapeptides according to the invention, discloses N-terminus enhanced pentapeptide compositions represented by formula (6):

    R.sup.1 -AA.sup.1 -AA.sup.2 -R.sup.2 -Pro.sup.1 -AA.sup.3 -Gly-R (SEQ ID NO:116)                                                   (6)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ and AA² each independently represent an amino acid of the group of Phe or Tyr; AA³ represents an amino acid of the group of Leu or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylarnino or dimethyl or diethylamino group.

An embodiment of the pentapeptides of formula (6) disclosed for utilization in treating depression in patients is formula (6a):

    R.sup.1 -AA.sup.1 -AA.sup.2 -R.sup.2 -Pro.sup.1 -AA.sup.3 -Gly-NH.sub.2 (SEQ ID NO:117)                                           (6a)

wherein Pro¹, AA¹, AA², R¹, and R² are as described for formula (6). Preferred compositions of the pentapeptides of formula (6a) include, but are not necessarily limited to, 4-F-Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:21), 4-Cl-Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:22), Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:23), Phe-Tyr-Pro-Ile-Gly-NH₂ (SEQ ID NO:24), Phe-Tyr-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:25), Phe-Tyr-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:26), Tyr-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:27), Tyr-Tyr-Pro-Ile-Gly-NH₂ (SEQ ID NO:28), Tyr-Tyr-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:29), and Tyr-Tyr-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:30).

Another embodiment of the pentapeptides according to the invention, discloses combined N-terminus and C-terminus enhanced pentapeptide compositions represented by formula (7):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(7)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, or Trp; AA³ represents the amino acid Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

An embodiment of pentapeptides of formula (7) discloses for utilization in treating depression in patients is formula (7a):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2(7a)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7). Preferred compositions of the pentapeptides of formula (7a) include, but are not necessarily limited to, Phe-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:31), Tyr-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:32), Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:33), Phe-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:34), Phe-cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:35), Tyr-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:36), Tyr-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:37), Tyr-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:38), Tyr-Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:39), Tyr-cis- or trans-4-OH-Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:40), 4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-Tip-NH₂ (SEQ ID NO:41), Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:42), 4-F-Phe-cis-or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43), 4-F-Phe-cis- or trans-4-OH-Pro-D-Arg-Gly-Trp-NH₂, 3-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:66); 2-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:68); and 4-Cl-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:61).

An additional group of preferred compositions of the pentapeptides of formula (7a) is characterized by the optional modification of Pro¹ to dehydro-Pro, preferably 3,4-dehydro-Pro. Additional preferred peptides of formula (7a) include but are not limited to 4-F-Phe-3,4-dehydro-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:72) and 4-F-Phe-3,4-dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:55).

Another group of embodiments encompassed within formula (7a) include, but are not solely limited to, additional optional modifications at AA², preferably Arg, His, Homo-Arg, L-Allo-Ile or canavanine; additional optional modifications at R¹ and/or R² (preferably R¹) and preferably an amino group, a carboxyl group, a nitro group, or a phosphono group (preferably as phosphono-Try); additional optional modification of the heterocyclic nitrogen ring of Pro¹, preferably cis- or trans-4-OH or Homo-Pro. Additional preferred peptides of formula (7a) are 4-NH₂ -Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:63); 4-F-Phe-cis- or trans-4-OH-Pro-His-Gly-Trp-NH₂ (SEQ ID NO:64); 4-NO₂ -Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:65); 4-CH₃ O-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:59); 4-F-Phe-cis- or trans-4-OH-Pro-Homo-Arg-Gly-Trp-NH₂ (SEQ ID NO:71); 4-F-Phe-Homo-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:69); 4-F-Phe-Homo-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:57); and 4-F-Phe-cis- or trans-4-OH-Pro-L-Allo-Ile-Gly-Trp-NH₂ (SEQ ID NO:73).

Another embodiment of pentapeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7b):

    R.sup.1 -AA -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2(7b)

wherein AA¹ is Phe; and Pro¹, AA², R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH- and trans-3-OH-; and additional optional modifications at R¹, preferably two or more halogen atoms, or a cyano group. Preferred compositions of the pentapeptides of formula (7b) include, but are not necessarily limited to, 3,4-Dichloro-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:76), 4-NC-Phe-cis- or treins-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:77), 4-F-Phe-cis- or trans-4-OH-Pro-D-Leu-Gly-Trp-NH₂ (SEQ NO:78), 4-F-Phe-trans-3-Hydroxy-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:79).

Another embodiment of pentapeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7c):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp   (7c)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with additional optional modifications at AA², preferably Homo-Arg; and additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-4-OH- and trans-3-OH-. A preferred composition of the pentapeptides of formula (7c) is 4-F-Phe-cis- or trans-4-OH-Pro-Homo-Arg-Gly-Trp (SEQ ID NO:74).

Another embodiment of pentapeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7d):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(7d)

wherein Pro¹, AA¹, AA², AA³, R¹, R² and R are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; additional optional modifications at Pro¹, preferably Homo-Pro; additional optional modifications at AA¹, preferably PhenylGly; additional optional modifications at AA³, preferably AzaTrp; additional optional modifications at R¹, preferably a haloform, or a methoxyl group; and additional optional modifications at R, preferably two or more halogen atoms or a hydroxyamino group. Preferred compositions of the pentapeptides of formnula (7d) include, but are not necessarily limited to, 4-CH₃ O-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NIH₂ (SEQ NO:81), 2,4-Di-F-Phe-3,4-Dihydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:82), 4-CF₃ -Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:83), 4-F-PhenylGly-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:84), 3-F-Tyr-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:85), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NHOH (SEQ NO:86), 3,4-Di-Cl-Phe-3,4-Dihydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:87), 2-F-Tyr-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:88), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-7-AzaTrp-NH₂ (SEQ NO:89).

Another embodiment of pentaipeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7e):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -Trp-NH.sub.2( 7e)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and R⁴ represents a modification of the tryptophan residue at one of C4, C5, C6 and C7 with a halogen atom, a hydroxyl group, or an alkyl group. Preferred compositions of the pentapeptides of formula (7e) include, but are not necessarily limited to, 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:107), 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-7-Methyl-Trp-NH₂ (SEQ NO:108).

Another embodiment of pentapeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7f):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -R.sup.5 -AA.sup.2 -Gly-Trp-NH.sub.2( 7f)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and R⁵ represents at least one halogen atom. A preferred composition of the pentapeptides of formula (7f) is 4-F-Phe-cis- or trans-4-OH-Pro-5,5,5-Trifluoro-Leu-Gly-Trp-NH₂ (SEQ NO:109).

Another embodiment of pentapeptides of formula (7) disclosed for utilization in treating depression in patients is formula (7g):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -AA.sup.3 -R(7g)

wherein Pro¹, AA¹, AA², AA³, R¹, R² and R are as described for formula (7) with the following additional optional modifications at Pro¹, preferably Homo-Pro; additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and R⁴ represents a halogen atom, a methyl group, a methoxyl group or a hydroxyl group. Preferred compositions of the pentapeptides of formula (7g) include, but are not necessarily limited to, 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:90), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-F-Trp-NH₂ (SEQ NO:91), 4-F-Phe-3,4-Dihydro-Pro-Arg-Gly-6-F-Trp-NH₂ (SEQ NO:92), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-3-CH₃ O-Trp-NH₂ (SEQ NO:93), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-N-Methyl-Trp-NH₂ (SEQ NO:94), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-1-Methyl-Trp-NH₂ (SEQ NO:95), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-Methyl-Trp-NH₂ (SEQ NO:96), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Methyl-Trp-NH₂ (SEQ NO:97), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-6-Methyl-Trp-NH₂ (SEQ NO:98), 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Hydroxy-Trp-NH₂ (SEQ NO:99).

Another embodiment of the pentapeptides according to the invention, discloses internal and C-terminus enhanced pentapeptide compositions represented by formula (8):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R (SEQ ID NO:118)(8)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ and AA² each independently represent an amino acid of the group of Leu or Ile; AA³ represents the amino acid Trp; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino group or dimethyl or diethylamino group.

An embodiment of pentapeptides of formula (8) disclosed for utilization in treating depression in patients is formula (8a):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2 (SEQ NO:119)(8a)

wherein Pro¹, AA¹, AA², and R¹ are as described for formula (8). Preferred compositions of the pentapeptides of formula (8a) include, but are not necessarily limited to, Pro-Ile-Leu-Gly-Trp-NH₂ (SEQ ID NO:44) and cis- or trans-4-OH-Pro-Ile-Leu-Gly-Trp-NH₂ (SEQ ID NO:45).

In another embodiment of the invention, pentapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (9):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(9)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents the amino acid Ala; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a pyridyl ring, preferably as a 3-(3-pyridyl) moiety; R² represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

A preferred composition of formula (9), but not to be construed as a limitation, is 3-(3-pyridyl)-Ala-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:70).

In another embodiment of the invention, hexapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (10):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -Gly-AA.sup.3 -R(10)

where Pro¹ represents the amino acid Pro or dehydro-Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp; AA⁴ represents the amino acid Gly or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

A preferred composition of formula (10), but not to be construed as a limitation, is 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ NO:80).

A group of preferred compositions of the hexapeptides of formula (10) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of a C-terminus amino acid of Trp, optional modification of the heterocyclic nitrogen ring of Pro¹, preferably a cis- or trans-4-OH group, a fluorine atom at position 4 of Phe; preferably Arg at AA² ; Tpr at AA³ ; and Ile or Gly at AA⁴, and by having the C-terminus amide remain unmodified. Formula (10a) is depicted as:

    R.sup.1 -Phe-R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -Gly-Trp-NH.sub.2(10a)

wherein preferred peptides of formula (10a) include but are not limited to 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ ID NO:58) and 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Ile-Gly-Trp-NH₂ (SEQ, ID NO:67).

In another embodiment of the invention, heptapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (11):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -AA.sup.5 -Gly-AA.sup.3 -R                                          (11)

where Pro¹ represents the amino acid Pro or dehydro-Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp; AA⁴ and AA¹ represent the amino acid Gly or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group, or a phoshphono group (preferably as phosphono-tyrosine).

A preferred composition of formula (11) includes but is not limited to 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Ile-Gly-Trp-NH₂ (SEQ ID NO:56).

In another embodiment of the invention, tetrapeptide compositions or pharmaceutically acceptable salts thereof including replacement of Pro with Arg; addition of an N-terminus amino acid of Phe to Arg; addition of a C-terminus amino acid of Trp to Gly; and modification of the aromatic ring of Phe can be represented by the following formula (12):

    R.sup.1 -Phe-R.sup.2 -Arg-Gly-Trp-NH.sub.2 (SEQ ID NO:120) (12)

where R¹ represents a halogen atom and R² represents a carboxylic acid of a monocyclic organic compound with a three to six membered ring structure having a hetero nitrogen atom. Preferred compositions of the pentapeptides of formula (12) include, but are not necessarily limited to, 4-F-Phe-isonipecotic acid-Arg-Gly-Trp-NH₂ (4-pyridinecarboxylic acid) (SEQ NO:100), 4-F-Phe-2-Carboxy-Azetidine-Arg-Gly-Trp-NH₂ (SEQ NO:101), 4-F-Phe-2-carboxy-Aziridine-Arg-Gly-Trp-NH₂ (SEQ NO:103), 4-F-Phe-3-Carboxy-1,4,5,6-Tetrahydropyridine-Arg-Gly-Trp-NH₂ (SEQ NO:105), 4-F-Phe-2-Carboxypyrrole-Arg-Gly-Trp-NH₂ (SEQ NO:106).

In another embodiment of the invention, pentapeptide compositions or pharmaceutically acceptable salts thereof including replacement of Pro with Arg; addition of an N-terminus amino acid of Phe to Arg; addition of an internal amino acid; addition of a C-terminus amino acid of Trp to Gly; and modification of the aromatic ring of Phe can be represented by the following formula (13):

    R.sup.1 -Phe-AA.sup.1 -Arg-Gly-Trp-NH.sub.2 (SEQ ID NO:122)(13)

where AA¹ represents an amino acid selected from the group comprising 1-amino-1-carboxycyclopentane and 1-amino-1-carboxy-cyclopropyl and R¹ represents a halogen atom. Preferred compositions of the pentapeptides of formula (13) include, but are not necessarily limited to, 4-F-Phe-1-Amino-1-Carboxycyclopentane-Arg-Gly-Trp-NH₂ (SEQ NO:102) and 4-F-Phe-1-Amino-1-Carboxy-Cyclopropyl-Arg-Gly-Trp-Nq (SEQ NO:104).

It is also disclosed that Gly of formula (7) through formula (11) may be optionally substituted with Val, Sar or Ala. One preferred peptide composition wherein Gly is substituted with Sar in formula (7) is 4-F-Phe-3,4-Dehydro-Pro-Arg-Sar-Trp-NH₂ (SEQ NO:110).

Especially preferred compositions of the present invention encompass small peptides which show increased higher activity in the Porsolt swim test described within this specification. These small peptides may vary in length, with the preferred peptides being tetrapeptides, pentapeptides, hexapeptides and heptapeptides. The formula for these especially preferred peptides, which are disclosed throughout this specification, may be:

    R.sup.1 -Phe-Pro.sup.1 -AA.sup.2 -AA.sup.3 -NH.sub.2 (SEQ ID NO:121),

for a tetrapeptide, wherein R¹ is preferably a halogen atom, most preferably a fluorine or chlorine atom, a carboxyl group, an amino group or a nitro group, with all modifications preferably at the C4 atom of Phe; Pro¹ is 3,4-dehydro Pro, Homo-Pro, cis- or trans-4OH-Pro or Pro, as listed in order of preference, AA² is preferably Ile, Leu or Arg; and AA³ is preferably Gly or Trp.

Another preferred tetrapeptide of the present invention is Pro-Ile-Gly-Trp (SEQ ID NO:3).

The formula for the especially preferred pentapeptides, hexapeptides and heptapeptides, which are also disclosed throughout this specification, may be:

    R.sup.1 -Phe-Pro.sup.1 -AA.sup.2 -Gly-AA.sub.(n) -AA.sup.3 -NH.sub.2,

wherein R¹ is preferably a halogen atom, preferably a fluorine or chlorine atom, a carboxyl group, an amino group or a nitro group, with all modifications preferably at the C4 atom of Phe; Pro¹ is 3,4-dehydro Pro, Homo-Pro, cis- or trans-4OH-Pro or Pro, as listed in order of preference, AA² is preferably Arg, Ile, Leu or His, with Arg being especially preferred; AA.sub.(n) is 0-2 amino acid residues, if n=1, then Gly is preferred and if n=2, then Ile-Gly, Ile-Ile or Gly-Gly is preferred; AA³ is preferably Trp or Gly, with Trp most preferred.

The present invention further discloses polypeptides of chemical combinations and/or overlapping chemical combinations of any of the peptides of formula (1) through formula (11) disclosed for utilization in treating depression in patients. These chemically combined polypeptides preferably have from at least about three to at least about ten modified and/or unmodified amino acids.

The present invention further discloses admixtures of the peptides of formula (1) through formula (11) with known antidepressant compounds such as amitriptyline, fluoxetine (Prozac) and sertraline (Zoloft). It is within the ordinary skill of the artisan to generate various admixtures with the small peptides of the present invention beyond the exemplifications disclosed throughout this specification.

The small peptides of the present invention should be formulated in a suitable pharmaceutical carrier for in vivo administration to the patient by any standard method known in the art such that a pharmacologically effective concentration reaches the site of action. Appropriate routes of administration include, but are not limited to, oral (mouth or peroral administration), sublingual, parenteral (e.g., intravenous, intraspinal, intrathecal, intraventricular, epidermal, intracisternal, intracutaneous or intradermal, subcutaneous, or intramuscular), epicutaneous or transdermal, intranasal or rectal as well as inhalation (poly or mircodispersed aerosol).

4.1 DEFINITIONS

The terms listed below, as used herein, will have the meaning indicated.

    ______________________________________                                         Pro       L-proline;                                                                      Leu L-leucine;                                                        Gly L-glycine;                                                                 Tyr L-tyrosine;                                                                Ala L-alanine;                                                                 Arg L-arginine;                                                                Lys L-lysine;                                                                  Phe L-phenylalanine;                                                           Trp L-tryptophan;                                                              Ile L-isoleucine;                                                              Orn L-ornithine;                                                               D-Arg D-arginine;                                                              D-Leu D-leucine;                                                               3,4-dehydro-Pro- 3,4-dehydro-L-proline;                                        pGlu pyro-glutamic acid;                                                       Sar L-sarcosine (N-methylglycine);                                             4-OH-Pro 4-hydroxyproline;                                                     4-thio-Pro 4-thioproline;                                                      2-F-Phe 2-fluorophenylalanine;                                                 3-F-Phe 3-fluorophenylalanine;                                                 4-F-Phe 4-fluorophenylalanine;                                                 4-Cl-Phe 4-chlorophenylalanine;                                                4-NH.sub.2 -Phe 4-aminophenylalanine;                                          3(3-pyridyl)Ala- 3(3-pyridyl)-alanine                                          Homo-Arg Homo-arginine                                                         Homo-Pro Homo-proline                                                          Fmoc 9-Fluorenylmethoxycarbonyl;                                               TFA trifluoroacetic acid;                                                      carboxyl carboxylic acid group or --CO.sub.2 H or --RCO.sub.2 H where                    R represents a monocyclic organic compound with a                     three to six member ring structure having a hetero                             nitrogen atom;                                                                hydroxyalkyl alcohol group or --ROH where R represents a lower                  alkyl group, preferably having 1 to 3 carbon atoms;                           carbamyl 1° amide group or --CONH.sub.2 or --RCONH2 where R                       represents a fused heterocyclic organic compound                      with a ten member ring structure having a hetero                               nitrogen atom;                                                                alkylcarbamyl 2° or 3° alkylated amide group or --CONR.sup               .1 R.sup.2 where                                                        R.sup.1 and R.sup.2 each independently represent a hydrogen                    atom, a lower alkyl group, preferably having 1 to 3                            carbon atoms;                                                                 alkoxycarbonyl ester group or --CO.sub.2 R where R represents a lower                    alkyl group, preferably having 1 to 3 carbon atoms                   dehydro anhydro group where one or more hydrogen atoms                          are removed;                                                                  hydroxyl alcohol group or --OH or --ROH where R represents                      a lower alkyl group, preferably having 1 to 3 carbon                           atoms;                                                                        sulphydryl thiol group --SH or --RSH where R represents a                       lower alkyl group, preferably having 1 to 3 carbon                             atoms;                                                                        alkylamino --NHR where R represents a lower alkyl group,                        preferably having 1 to 3 carbon atoms;                                        dialkylamino --NR.sub.2 where R represents a lower alkyl group,                          preferably having 1 to 3 carbon atoms;                               hydroxyamino --NHOH group;                                                     patient includes any member of the animal kingdom,                              including but not solely limited to humans; and,                              CGI Control group inactive.                                                  ______________________________________                                    

5. BRIEF DESCRIPTION OF THE FIGURES

There are shown in the Figures certain exemplary small peptide compositions of the invention and pharmacological efficacy thereof as antidepressants as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples in the figures and the accompanying Table 1, and is capable of variation within the scope of the appended claims. In the drawings,

FIG. 1 shows the average number of responding animals in the Porsolt swim test for selected compounds listed 1-15, as follows:

1. 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:55)

2. 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Ile-Gly-TRP-NH₂ (SEQ ID NO:56)

3. 4-F-Phe-4-Homo-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:57)

4. Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:3)

5. 4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:16)

6. Amitriptyline

7. 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Gly-Trp-NH, (SEQ ID NO:58)

8. 4-CH₃ O-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:59)

9. 4-Cl-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:60)

10. 4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:41)

11. 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43)

12. 4-OH-Pro-Ile-Gly-NH₂

13. Zoloft

14. Prozac, and

15. Pro-Leu-Gly-NH₂.

Peptides were administered at 0.1 mg/ml in these selected examples;

FIG. 2 shows the mean mobile time for difference between the CGI and selected compounds listed as 1-15, as above for FIG. 1; and,

FIG. 3 shows the mean of Z-score of calculated mobile time for selected compounds listed as 1-15, as above for FIG. 1.

6. DETAILED DESCRIPTION OF THE INVENTION

The tripeptide hormone fragment having the general formula Pro-Leu-Gly-NH₂, otherwise known as L-prolyl L-leucyl glycine, melanocyte stimulating inhibitory factor, melanotrophic release inhibiting factor, or MIF, is known to exhibit antidepressant activity. MIF is typically reported in literature as having the tripeptide structure Pro-Leu-Gly-NH₂ or Pro-Leu-Gly-amide. MIF will be referred to herein as Pro-Leu-Gly-NH₂ having the following chemical structure: ##STR1##

According to the invention, modifications of the tripeptide structure of MIF result in novel small peptides utilized to treat patients suffering from depression. These modifications target amino terminus residues, carboxyl terminus residues and internal residues, including addition and substitution of amino acid residues and modification of the peptide bonds and functional side groups of respective amino acid residues as more fully described hereinbelow.

In general, the amino acid(s) additions or substitutions at the amino terminus (N-terminus), carboxyl terminus (C-terminus), or internal amino acid residues to the MIF core sequence to synthesize the small peptides of the invention can be selected from the group of Ala, Arg, D-Arg, Gly, Ile, Leu, D-Leu, Lys, Orn, Phe, Pro, dehydro-Pro, Sar, Trp, and Tyr or any of the remaining amino acids. The carboxyl terminus modifications of the small peptides of the invention can include optional replacement of the carbamyl (amide) group at the carboxyl terminus of the MIF core sequence by a carboxyl (acid) group, a hydroxyalkyl (alcohol) group, an alkoxycarbonyl (ester) group, or an alkylcarbamyl (alkylated amide) group, and the like. The amino terminus and internal modifications of the small peptides of the invention can include optional additions or eliminations on the heterocyclic, aromatic, and other carbon residues of the amino acids with an alkyl group, preferably an alkyl group having 1 to 3 carbon atoms, a dehydro (anhydro) group, a halo group, a hydroxyl group, a sulphydryl group, an alkylamino group, or a dialkylamino group, and the like. Furthermore, the amino groups of the small peptides of the invention can be alkylated, preferably with an alkyl group having 1 to 3 carbon atoms. It should be understood by a person of ordinary skill that these additions, substitutions, eliminations, and/or modifications can be carried out by conventional polypeptide synthesis and organic chemistry synthesis techniques.

This specification details extensive biological data supporting the following premise: small peptides disclosed herein show substantial antidepressant activity as measured in the Porsolt swim test. The Example Section contains comparative data of exemplified peptides of the present invention and known antidepressants amitriptyline, fluoxetine (Prozac) and sertraline (Zoloft) generated in a series of Porsolt swim tests. The groupings of the small peptides of the invention into the formulas described below are provided only as a matter of convention and should not be considered limiting in any manner.

In one embodiment of the invention, the small peptides are tripeptides characterized either by optional replacement of the Leu residue of the MIF core sequence with an amino acid selected from the group of Trp, Orn, Lys, Arg, D-Arg, or Ile; optional replacement of the Pro residue with dehydro-Pro, preferably 3,4-dehydro-Pro; optional modification of the carboxyl terminus amide group with a substituent selected from a carboxyl group, an hydroxyalkyl group, preferably a hydroxymethyl group, an alkoxycarbonyl group, or an alkylated carbamyl group; optional modification of the amino terminus heterocyclic group or dehydro-heterocyclic group with a substituent selected from the group of a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group; or an alkylamino group or a dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group; and/or optional modification of the hydrogen atoms at the nitrogen atoms of the amino acid peptide bonds with a lower alkyl group, preferably having 1 to 3 carbon atoms.

This tripeptide composition or a pharmaceutically acceptable salt thereof can be represented by the following formula (1):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -NR.sup.2 -CH.sub.2 -R        (1)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Trp, Orn, Lys, Leu, Arg, D-Arg, or Ile; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino group or dimethyl or diethylamino group; and, R² represents a hydrogen atom or a lower alkyl group, preferably having 1 to 3 carbon atoms, with the proviso that where Pro¹ is Pro and AA¹ is Leu, then R¹ and R² cannot both be hydrogen when R is a carbamyl (amide) group, since MIF is a known compound.

The following paragraphs disclose compositions of the tripeptides of formula (1), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A first group of preferred compositions of the tripeptides of formula (1) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by replacement of Leu, and are further characterized by having the N-terminus Pro¹ residue and C-terminus amide group remain unmodified, which can be represented by formula (1a). Formula (1a) is depicted as:

    Pro.sup.1 -AA.sup.1 -Gly-NH.sub.2                          ( 1a)

wherein Pro¹ and AA¹ are as described above for formula (1). The tripeptides of formula (1a), may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression. Preferred compositions of the tripeptides of formula (1a) are:

Pro-Trp-Gly-NH₂ ;

Pro-Arg-Gly-NH₂ ;

Pro-D-Arg-Gly-NH₂ ;

Pro-Lys-Gly-NH₂ ;

Pro-Orn-Gly-NH₂ ;

and,

Pro-Ile-Gly-NH₂.

A second group of preferred compositions of the tripeptides of formula (1) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by optional replacement of Leu, and are further characterized by optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹, preferably at the C-4 position of the heterocyclic nitrogen ring, preferably by addition of a cis- or trans-hydroxyl group or a cis- or trans-sulphydryl group, and by having the C-terminus's amide group remain unmodified, which can be represented by formula (1b). Formula (1b) is depicted as:

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Gly-NH.sub.2                 ( 1b)

wherein Pro¹, AA¹ and R¹ are as described above for formula (1). Preferred compositions of the tripeptides of formula (1b) are:

cis- or trans-4-OH-Pro-D-Arg-Gly-NH₂ ;

cis- or trans-4-OH-Pro-Ile-Gly-NH₂ ;

cis- or trans-4-OH-Pro-Arg-Gly-NH₂ :

cis- or trans-4-OH-Pro-Trp-Gly-NH₂ ;

and,

cis- or trans-4-thio-Pro-Leu-Gly-NH₂.

A third group of preferred compositions of the tripeptides of formula (1) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by optional replacement of Leu, optional modification of the C-terminus amide group, optional modification of the C-terminus hydrogen atom at the nitrogen comprising the peptide bond between Leu-Gly, and by having the N-terminus heterocyclic nitrogen ring of Pro¹ remain unmodified, which can be represented by formula (1c). Formula (1c) is depicted as:

    Pro.sup.1 -AA.sup.1 -NR.sup.2 -CH.sub.2 -R                 (1c)

wherein Pro¹, AA¹, and R and R² are as described above for formula (1), with the proviso that where Pro¹ is Pro and AA¹ is Leu, R² cannot be hydrogen when R is either a carboxyl group or a hydroxyalkyl group, since the compounds of Pro-Leu-NHCH₂ -CO₂ H (or Pro-Leu-Gly) and Pro-Leu-NHCH₂ -CH₂ OH, do not form part of this invention, and with the further proviso that where Pro¹ is Pro and AA¹ is Trp, R² cannot be a hydrogen atom when R is a hydroxyalkyl group, since Pro-Trp-NHCH₂ -CH₂ OH is a known compound. Preferred compositions of the tripeptides of formula (1c) are:

Pro-Leu-N(CH₃)CH₂ -CONH₂ ;

and,

Pro-Trp-NHCH₂ -CO₂ H.

In another embodiment of the invention, additional tripeptides are characterized by replacement of Leu with Arg or D-Arg; replacement of Gly with Ala; optional replacement of Pro with dehydro-Pro, preferably 3,4-dehydro-Pro; optional modification of the C-terminus amide group with a functional group selected from the group of a carboxyl group, a hydroxyalkyl group, preferably a hydroxymethyl group, an alkoxycarbonyl group, or an alkylated carbamyl group; optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group of a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group; or an alkylamino group or a dialkylamino group, preferably a methyl or ethyl amino or dimethyl or diethyl amino group; and/or optional modification of the hydrogen atoms at the nitrogen atoms of the amino acid peptide bonds with a lower alkyl group, preferably having 1 to 3 carbon atoms.

This tripeptide composition or a pharmaceutically acceptable salt thereof can be represented by the following formula (2):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Ala-R                        (2)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Arg or D-Arg; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

The following paragraph discloses compositions of the tripeptides of formula (2), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the tripeptides of formula (2) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by replacement of the Leu and Gly, and by having the N-terminus Pro¹ residue and C-terminus amide remain unmodified, which can be represented by formula (2a). Formula (2a) is depicted as:

    Pro.sup.1 -AA.sup.1 -Ala-NH.sub.2                          ( 2a)

wherein Pro¹ and AA¹ are as described above for formula (2). Preferred compositions of the tripeptides of formula (2a) are:

Pro-Arg-Ala-NH₂ ;

and,

Pro-D-Arg-Ala-NH₂.

In a further embodiment according to the invention, the small tripeptides are characterized by replacement of Leu with Orn; replacement of Gly with Tyr; optional replacement of Pro with dehydro-Pro, preferably 3,4-dehydro-Pro; optional modification of the C-terminus amide group with a substituent selected from the group of a carboxyl group, a hydroxyalkyl group, preferably hydroxymethyl, an alkoxycarbonyl group, or an alkylated carbamyl group; optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group of a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino group or a dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group; and/or optional modification of the hydrogen atoms at the nitrogen atoms of the amino acid peptide bonds with a lower alkyl group, preferably having 1 to 3 carbon atoms.

This tripeptide composition or pharmaceutically acceptable salt thereof can be represented by the following formula (3):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Tyr-R                        (3)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents the amino acid Orn; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group.

The following paragraphs disclose compositions of the tripeptides of formula (3), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the tripeptides of formula (3) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by replacement of Leu and Gly, optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹, and by having the C-terminus amide remain unmodified, which can be represented by formula (3a). Formula (3a) is depicted as:

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Tyr-NH.sub.2                 ( 3a)

where Pro¹, AA¹ and R¹ are as described for formula (3). Preferred compositions of the tripeptides of formula (3a) are:

Pro-Orn-Tyr-NH₂ ;

and,

cis- or trans-4-OH-Pro-Orn-Tyr-NH₂.

In yet another embodiment according to the invention, the small peptides are tetrapeptides characterized by either addition of a C-terminus amino acid of Trp or Tyr to Gly or addition of a N-terminus amino acid of Trp or Phe to Pro to the tripeptides having the MIF core sequence; optional replacement of Leu with Ile, Arg, D-Arg, or Trp; optional replacement of Pro with dehydro-Pro, preferably 3,4-dehydro-Pro; optional modification of the C-terminus amide with a substituent selected from the group of a carboxyl group, a hydroxyalkyl group, preferably a hydroxymethyl group, an alkoxycarbonyl group, or an alkylated carbamyl group; optional modification of the heterocyclic nitrogen rings of Pro¹ and Trp and optional modification of the aromatic ring of Phe with a substituent selected from the group of a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or a dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group; and/or optional modification of the hydrogen atoms at the nitrogen atoms of the amino acid peptide bonds with a lower alkyl group, preferably having 1 to 3 carbon atoms.

One embodiment of the tetrapeptide compositions or pharmaceutically acceptable salt thereof including a C-terminus amino acid addition can be represented by the following formula (4):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -Gly-AA.sup.2 -R              (4)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Ile, Leu, Arg, D-Arg or Trp; AA² represents Trp or Tyr; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a dehydro group, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

The following paragraphs disclose compositions of the tetrapeptides of formula (4), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the tetrapeptides of formula (4) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of Trp or Tyr to the C-terminus Gly, by optional replacement of Leu, by optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹, and by having the C-terminus amide remain unmodified, which can be represented by formula (4a). Formula (4a) is depicted as:

    R.sup.1 -Pro-AA.sup.1 -Gly-AA.sup.2 -NH.sub.2              ( 4a)

wherein Pro¹, AA¹, AA², and R¹ are as described for formula (4). Preferred compositions of the tetrapeptides of formula (4a) are:

cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:1);

cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:2);

cis- or trans-4-OH-Pro-D-Arg-Gly-Trp-NH₂ ;

and,

3,4-dehydro-Pro-D-Arg-Gly-Trp-NH₂.

Another preferred composition of the tetrapeptide of formula (4a) is 3,4-dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:62).

A second group of preferred compositions of the tetrapeptides of formula (4) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of Trp or Tyr to the C-terminus Gly, by optional replacement of Leu, and by having the N-terminus heterocyclic nitrogen ring of Pro¹ remain unmodified, which can be represented by formula (4b). Formula (4b) is depicted as:

    Pro.sup.1 -AA.sup.1 -Gly-AA.sup.2 -NH.sub.2                ( 4b)

wherein Pro¹, AA¹ and AA² are as described for formula (4). Preferred compositions of the tetrapeptides of formula (4b) are:

Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:3);

3,4-dehydro-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:4);

Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:5);

Pro-Leu-Gly-Tyr-NH₂ (SEQ ID NO:6);

Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:7);

Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:8);

Pro-D-Arg-Gly-Trp-NH₂ ;

and,

Pro-Ile-Gly-Tyr-NH₂ (SEQ ID NO:9).

Another embodiment of the tetrapeptide compositions or pharmaceutically acceptable salt thereof including a N-terminus amino acid addition can be represented by the following formula (5):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R (SEQ ID NO:113)(5)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Trp, Tyr, or Phe; AA² represents an amino acid of the group of Leu, Ile, or Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, a sulphydryl group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

The following paragraphs disclose compositions of the tetrapeptides of formula (5), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the tetrapeptides of formula (5) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of Trp, Tyr, or Phe to the N-terminus Pro¹, optional replacement of Leu, optional modification of the heterocyclic nitrogen rings of Pro¹ and Trp and optional modification of the aromatic ring of Phe and Tyr, and by having the C-terminus amide remain unmodified, which can be represented by formula (5a). Formula (5a) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-NH.sub.2 (SEQ ID NO:114)                                                   (5a)

wherein Pro¹, AA¹, AA², R¹, and R² are as described for formula (5), with the proviso that where Pro¹ is Pro, R¹ and R² cannot both be a hydrogen atom when AA¹ is Tyr and AA² is Trp, since Tyr-Pro-Trp-Gly-NH₂ (SEQ ID NO:54) is a known compound, and with the further proviso that where Pro¹ is Pro and AA² is Leu, R¹ and R² cannot both be a hydrogen atom when AA¹ is Phe or Tyr, since Phe-MIF-1 and Tyr-MIF-1 are known compounds. Preferred compositions of the tetrapeptides of formula (5a) are:

Trp-Pro-Leu-Gly-NH₂ (SEQ ID NO:10);

Phe-Pro-Leu-Gly-NH₂ (SEQ ID NO:11);

4-F-Phe-Pro-Iu-Gly-NH₂ (SEQ ID NO:12);

4-Cl-Phe-Pro-Leu-Gly-NH₂ (SEQ ID NO:13);

4-F-Phe-Pro-Ile-Gly-NH₂ (SEQ ID NO:14);

4-F-Phe-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:15);

4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:16);

Trp-Pro-Leu-Gly-NH₂ (SEQ ID NO:17);

Trp-Pro-Ile-Gly-NH₂ (SEQ ID NO:18);

Trp-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:19);

and,

Trp-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:20)

An additional preferred composition of the tetrapeptide of formula (5a) is 4-Cl-Phe-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:60).

Another group of preferred compositions of the tetrapeptides of formula (5) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of Phe to the N-terminus Pro¹, optional replacement of Leu with Arg, optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic ring of Phe, and by modification of the C-terminus amide to a carbamyl group, which can be represented by formula (5b). Formula (5b) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R (SEQ ID NO:115)(5b)

wherein Pro¹, AA¹, AA², R¹, R² and R are as described for formula (5). Preferred compositions of the tetrapeptides of formula (5b) include, but are not solely limited to, additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a cis- or trans-4-OH- group; and additional optional modifications at AA², preferably Arg. A preferred peptide of formula (5b) is 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-1,2,3,4-Tetrahydroisoquinoline-3-carboxamide (SEQ NO:75).

In yet another embodiment of the invention, the peptides are pentapeptides with either addition of two N-terminus amino acids of Phe, Tyr, Leu, or Ile to Pro¹, addition of a N-terminus amino acid of Phe or Tyr to Pro¹ and a C-terminus amino acid addition of Trp to Gly, or addition of a C-terminus amino acids of Trp to Gly and an internal amino acid between Pro¹ and Gly, to tripeptides having the MIF core sequence; optional replacement of Leu with Ile or Trp: optional replacement of Pro with dehydro-Pro, preferably 3,4-dehydro-Pro; optional modification of the C-terminus amide with a substituent selected from the group of a carboxyl group, a hydroxyalkyl group, preferably a hydroxymethyl group, an alkoxycarbonyl group, or an alkylated carbamyl group; optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Tyr or Phe with a substituent selected from the group of a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or a dialkylamino group, preferably a methyl or ethylamino or a dimethyl or diethylamino group; and/or optional modification of the hydrogen atoms at the nitrogen atoms of the amino acid peptide bonds with a lower alkyl group, preferably having 1 to 3 carbon atoms.

One embodiment of the pentapeptide compositions including addition of two N-terminus amino acids or pharmaceutically acceptable salt thereof can be represented by the following formula (6):

    R.sup.1 -AA.sup.1 -AA.sup.2 -R.sup.2 -Pro.sup.1 -AA.sup.3 -Gly-R (SEQ ID NO:116)                                                   (6)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ and AA² each independently represent an amino acid of the group of Phe or Tyr; AA¹ represents an amino acid of the, group of Leu or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

The following paragraph dicloses compositions of the pentapeptides of formula (6), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the pentapeptides of formula (6) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of two N-terminus amino acids of Phe and Tyr to Pro¹, optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe or Tyr, optional replacement of Leu, and by having the C-terminus amide of Gly remain unmodified, which can be represented by formula (6a). Formula (6a) is depicted as:

    R.sup.1 -AA.sup.1 -AA.sup.2 -R.sup.2 -Pro.sup.1 -AA.sup.1 -Gly-NH.sub.2 (SEQ ID NO:117)                                           (6a)

wherein Pro¹, AA¹, AA², R¹, and R² are as described for formula (6). Preferred pentapeptides of formula (6a) are:

4-F-Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:21);

4-Cl-Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:22);

Phe-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:23);

Phe-Tyr-Pro-Ile-Gly-NH₂ (SEQ ID NO:24);

Phe-Tyr-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:25);

Phe-Tyr-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:26);

Tyr-Tyr-Pro-Leu-Gly-NH₂ (SEQ ID NO:27);

Tyr-Tyr-Pro-Ile-Gly-NH₂ (SEQ ID NO:28);

Tyr-Tyr-cis- or trans-4-OH-Pro-Leu-Gly-NH₂ (SEQ ID NO:29);

and,

Tyr-Tyr-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:30).

In another embodiment of the invention, pentapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (7):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(7)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, or Trp; AA³ represents the amino acid Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

The following paragraph discloses compositions of the pentapeptides of formula (7), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of a N-terminus amino acid of Phe or Tyr to Pro¹, addition of a C-terminus amino acid of Trp to Gly, optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe or Tyr, optional replacement of Leu with Ile, Arg, D-Arg, or Trp, and by having the C-terminus amide remain unmodified, which can be represented by formula (7a). Formula (7a) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2( 7a)

wherein Pro¹, AA¹, AA², R¹, and R² are as described for formula (7). Preferred pentapeptides of formula (7a) are:

Phe-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:31);

Tyr-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:32);

Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:33);

Phe-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:34);

Phe-cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:35);

Tyr-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:36);

Tyr-Pro-Ile-Gily-Trp-NH₂ (SEQ ID NO:37);

Tyr-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:38);

Tyr-Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:39);

Tyr-cis- or trans-4-OH-Pro-Trp-Gly-Trp-NH₂ (SEQ ID NO:40);

4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:41);

4-F-Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:42);

4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43);

and,

4-F-Phe-cis- or trans-4-OH-Pro-D-Arg-Gly-Trp-NH₂.

An additional embodiment regarding preferred pentapeptides of formula (7a), included but is not solely limited to:

3-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:66);

2-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:68); and

4-Cl-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:61).

An additional group of preferred compositions of the pentapeptides of formula (7a) is characterized by the optional modification of Pro¹ to dehydro-Pro, preferably 3,4-dehydro-Pro. Additional preferred peptides of formula (7a) include but are not limited to:

4-F-Phe-3,4-dehydro-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:72); and

4-F-Phe-3,4-dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:55).

Another group of embodiments encompassed within formula (7a) include, but are not solely limited to, additional optional modifications at AA², preferably Arg, His, Homo-Arg, L-Allo-Ile, or canavanine; additional optional modifications at R¹ and/or R² (preferably R¹) and preferably an amino group, a carboxyl group, a nitro group, or a phosphono group (preferably as phosphono-Tyr); additional optional modification of the heterocyclic nitrogen ring of Pro¹, preferably cis- or trans-4-OH or Homo-Pro. Additional preferred peptides of formula (7a) are:

4-NH₂ -Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:63);

4-F-Phe-cis- or trans-4-OH-Pro-His-Gly-Trp-NH₂ (SEQ ID NO:64);

4-NO₂ -Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:65);

4-CH₃ O-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:59);

4-F-Phe-cis- or trans-4-OH-Pro-Homo-Arg-Gly-Trp-NH₂ (SEQ ID NO:71);

4-F-Phe-Homo-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:69);

4-F-Phe-Homo-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:57); and,

4-F-Phe-cis- or trans-4-OH-Pro-L-Allo-Ile-Gly-Trp-NH₂ (SEQ ID NO:73).

A group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe; addition of a C-terminus amino acid of Trp to Gly; optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic ring of Phe; and by having the C-terminus amide remain unmodified, which can be represented by formula (7b). Formula (7b) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2( 7b)

wherein AA¹ is Phe; and Pro¹, AA, R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and additional optional modifications at R¹, preferably two or more halogen atoms or a cyano group. Preferred compositions of the pentapeptides of formula (7b) include, but are not necessarily limited to:

3,4-Dichloro-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:76);

4-NC-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:77);

4-F-Phe-cis- or trans-4-OH-Pro-D-Leu-Gly-Trp-NH₂ (SEQ NO:78); and,

4-F-Phe-trans-3-Hydroxy-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:79).

A group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe, addition of a C-terminus amino acid of Trp to Gly, optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic ring of Phe, and the absence of the C-terminus amide, which can be represented by formula (7c). Formula (7c) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp   (7c)

where Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with additional optional modifications at AA², preferably Homo-Arg; and additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH- and trans-3-OH. A preferred peptide of formula (7c) is 4-F-Phe-cis- or trans-4-OH-Pro-Homo-Arg-Gly-Trp (SEQ NO:74).

Another group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe, Tyr or PhenylGly; addition of a C-terminus amino acid of Trp or AzaTrp to Gly; optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe, Tyr and PhenylGly; and additional optional modification at R, preferably a hydroxyamino group, which can be represented by formula (7d). Formula (7d) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(7d)

wherein Pro¹, AA¹, AA², AA³, R¹, R² and R are as described for formula (7) with the following additional optional modifications at Pro¹, preferably Homo-Pro; additional optional modifications at AA¹, preferably PhenylGly; additional optional modifications at AA³, preferably AzaTrp; additional optional modifications at R¹, preferably two or more halogen atoms, a haloform, or a methoxyl group; additional optional modifications at R², preferably a cis- or trans-3-OH- group; and additional optional modifications at R, preferably a hydroxyamino group. Preferred compositions of the pentapeptides of formula (7d) include, but are not necessarily limited to:

4-CH₃ O-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO :81);

2,4-Di-F-Phe-3,4-Dihydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:82);

4-CF₃ -Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:83);

4-F-PhenylGly-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:84);

3-F-Tyr-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:85);

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NHOH (SEQ NO:86);

3,4-Di-CI-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:87);

2-F-Tyr-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ NO:88); and,

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-7-AzaTrp-NH₂ (SEQ NO:89).

Another group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe; addition of a C-terminus amino acid of Trp to Gly; optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe and Trp; and by having the C-terminus amide remain unmodified, which can be represented by formula (7e). Formula (7e) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -Trp-NH.sub.2( 7e)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and R⁴ represents a modification of the tryptophan residue at one of C4, C5, C6 and C7 with a halogen atom, a hydroxyl group, or an alkyl group. Preferred compositions of the pentapeptides of formula (7e) include, but are not necessarily limited to:

4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:107); and,

4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-7-Methyl-Trp-NH₂ (SEQ NO:108).

Another group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe; addition of a C-terminus amino acid of Trp to Gly; optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe and Leu; and by having the C-terminus amide remain unmodified, which can be represented by formula (7f). Formula (7f) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -R.sup.5 -AA.sup.2 -Gly-Trp-NH.sub.2( 7f)

wherein Pro¹, AA¹, AA², R¹ and R² are as described for formula (7) with the following additional optional modification of the N-terminus heterocyclic nitrogen ring of Pro¹ with a substituent selected from the group consisting of cis-4-OH-, trans-4-OH-, cis-3-OH-, and trans-3-OH-; and R⁵ represents at least one halogen atom. A preferred composition of the pentapeptides of formula (7f) is 4-F-Phe-4-OH-Pro-5,5,5-Trifluoro-Leu-Gly-Trp-NH₂ (SEQ NO:109).

Another group of preferred compositions of the pentapeptides of formula (7) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of an N-terminus amino acid of Phe; addition of a C-terminus amino acid of Trp to Gly; additional optional modifications at Pro¹, preferably Homo-Pro; optional modification of the heterocyclic nitrogen ring of Pro¹ and optional modification of the aromatic rings of Phe and Trp; and by having the C-terminus amide remain unmodified, which can be represented by formula (7g). Formula (7g) is depicted as:

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -AA.sup.3 -R(7g)

wherein Pro¹, AA¹, AA², AA³, R¹, R² and R are as described for formula (7) with the following additional optional modifications at Pro¹, preferably Homo-Pro or 3,4-dihydro-Pro; additional optional modifications at R², preferably cis- or trans-3-OH- group; and R⁴ represents a halogen atom, a methyl group, a methoxyl group or a hydroxyl group. Preferred compositions of the pentapeptides of formula (7g) include, but are not necessarily limited to:

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:90)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-F-Trp-NH₂ (SEQ NO:91)

4-F-Phe-3,4-Dihydro-Pro-Arg-Gly-6-F-Trp-NH₂ (SEQ NO:92)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-3-CH₃ O-Trp-NH₂ (SEQ NO:93)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-N-Methyl-Trp-NH₂ (SEQ NO:94)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-1-Methyl-Trp-NH₂ (SEQ NO:95)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-Methyl-Trp-NH₂ (SEQ NO:96)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Methyl-Trp-NH₂ (SEQ NO:97)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-6-Methyl-Trp-NH₂ (SEQ NO:98)

4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Hydroxy-Trp-NH₂ (SEQ NO:99).

In yet another embodiment of the invention, pentapeptide compositions or pharmaceutically acceptable salt thereof including addition of a C-terminus amino acid and an internal amino acid can be represented by the following formula (8):

    R.sup.1 -Pro.sup.1 -AA.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R (SEQ ID NO:118)(8)

where Pro¹ represents the amino arid Pro or dehydro-Pro, preferably 3,4-dehydro-Pro; AA¹ and AA² each independently represent an amino acid of the group of Leu or Ile; AA³ represents Trp; R represents a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH-group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino group or dimethyl or diethylamino group.

The following paragraph discloses compositions of the pentapeptides of formula (8), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the pentapeptides of formula (8) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of a C-terminus amino acid of Trp to Gly, addition of an internal amino acid of Leu or Ile between Pro¹ and Gly, optional modification of the heterocyclic nitrogen ring of Pro¹, optional replacement of Leu with Ile, and by having the C-terminus amide remain unmodified, which can be represented by formula (8a). Formula (8a) is depicted as:

    R.sup.1 -Pro.sup.1 -AA.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2 (SEQ ID NO:119)(8a)

wherein Pro¹, AA¹, AA², and R¹ are as described for formula (8). Preferred pentapeptides of formula (8a) are:

Pro-Ile-Leu-Gly-Trp-NH₂ (SEQ ID NO:44),

and,

cis- or trans-4-OH-Pro-Ile-Leu-Gly-Trp-NH₂ (SEQ ID NO:45).

In another embodiment of the invention, pentapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid c,an be represented by the following formula (9):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-AA.sup.3 -R(9)

where Pro¹ represents the amino acid Pro or dehydro-Pro, preferably 3,4-dehydro Pro; AA¹ represents the amino acid Ala; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ represents a pyridyl ring, preferably as a 3-(3-pyridyl) moiety; R² represents a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

A preferred composition of formula (9) includes but is not limited to:

3-(3-pyridyl)-Ala-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:70).

In another embodiment of the invention, hexapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (10):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -Gly-AA.sup.3 -R(10)

where Pro¹ represents the amino acid Pro or dehydro-Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp: AA⁴ represents the amino acid Gly or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamino or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group.

A preferred composition of formula (10), but not to be construed as a limitation, is 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ NO:80).

A group of preferred compositions of the hexapeptides of formula (10) which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by addition of a C-terminus amino acid of Trp, optional modification of the heterocyclic nitrogen ring of Pro¹, preferably a cis- or trans-4-OH group, a fluorine atom at position 4 of Phe; preferably Arg at AA² ; Tpr at AA³ ; and Ile or Gly at AA⁴, and by having the C-terminus amide remain unmodified, which can be represented by formula (10a). Formula (10a) is depicted as:

    R.sup.1 -Phe-R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 Gly-Trp-NH.sub.2( 10a)

wherein preferred peptides of formula (10a) are:

4-F-Phe-4-OH-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ ID NO:58); and

4-F-Phe-4-OH-Pro-Arg-Ile-Gly-Trp-NH₂ (SEQ ID NO:67).

In another embodiment of the invention, heptapeptide compositions or pharmaceutically acceptable salt thereof including addition of both a N-terminus amino acid and a C-terminus amino acid can be represented by the following formula (11):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -AA.sup.5 -Gly-AA-R                                                 (11)

where Pro¹ represents the amino acid Pro or dehydro-Pro; AA¹ represents an amino acid of the group of Phe or Tyr; AA² represents an amino acid of the group of Leu, Ile, Arg, D-Arg, Trp, or canavanine; AA³ represents the amino acid Trp: AA⁴ and AA⁵ represent the amino acid Gly or Ile; R represents a carboxyl group, hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, or an alkoxycarbonyl group; and, R¹ and R² each independently represent a hydrogen atom, a lower alkyl group, preferably having 1 to 3 carbon atoms, a halogen atom, preferably a fluorine or chlorine atom, a hydroxyl group, preferably a cis- or trans-4-OH- group, a sulphydryl group, preferably a cis- or trans-4-thio- group, or an alkylamine or dialkylamino group, preferably a methyl or ethylamino or dimethyl or diethylamino group, or a phosphono group (preferably as phosphono-Tyr).

A preferred composition of formula (11) is:

4-F-Phe-4-OH-Pro-Arg-Gly-Ile-Gly-Trp-NH₂ (SEQ ID NO:56).

The following paragraph discloses compositions of the tetrapeptides of formula (12) or pharmaceutically acceptable salt thereof, which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the tetrapeptides of formula (12) or pharmaceutically acceptable salt thereof which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by replacement of Pro with Arg; addition of an N-terminus amino acid of Phe to Arg; addition of a C-terminus amino acid of Trp to Gly; optional modification of the aromatic rings of Phe and by having the C-terminus amide remain unmodified, which can be represented by formula (12). Formula (12) is depicted as:

    R.sup.1 -Phe-R.sup.2 -Arg-Gly-Trp-NH.sub.2 (SEQ ID NO:120) (12)

where R¹ represents a halogen atom and R² represents a carboxylic acid of a monocyclic organic compound with a three to six membered ring structure having a hetero nitrogen atom. Preferred compositions of the pentapeptides of formula (12) include, but are not necessarily limited to:

4-F-Phe-isonipecotic acid-Arg-Gly-Trp-NH₂ (4-pyridinecarboxylic acid) (SEQ NO:100)

4-F-Phe-2-Carboxy-Azetidine-Arg-Gly-Trp-NH₂ (SEQ NO:101)

4-F-Phe-2-carboxy-Aziridine-Arg-Gly-Trp-NH₂ (SEQ NO:103)

4-F-Phe-3-Carboxy-1,4,5,6-Tetrahydropyridine-Arg-Gly-Trp-NH₂ (SEQ NO:105)

4-F-Phe-2-Carboxypyrrole-Arg-Gly-Trp-NH₂ (SEQ NO:106).

The following paragraph discloses compositions of the pentapeptides of formula (13), which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression.

A group of preferred compositions of the pentapeptides of formula (13) or a pharmaceutically acceptable salt thereof which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression are characterized by replacement of Pro with Arg; addition of an N-terminus amino acid of Phe to Arg; addition of an internal amino acid; addition of a C-terminus amino acid of Trp to Gly; optional modification of the aromatic ring of Phe and by having the C-terminus amide remain unmodified, which can be represented by formula (13). Formula (13) is depicted as:

    R.sup.1 -Phe-AA.sup.1 -Arg-Gly-Trp-NH.sub.2 (SEQ ID NO:122)(13)

where AA¹ represents an amino acid selected from the group comprising 1-amino-1-carboxycyclopentane and 1-amino-1-carboxy-cyclopropyl and R¹ represents a halogen atom. Preferred compositions of the pentapeptides of formula (13) include, but are not necessarily limited to, 4-F-Phe-1-Amino-1-Carboxycyclopentane-Arg-Gly-Trp-NH₂ (SEQ NO:102) and 4-F-Phe-1-Amino-1-Carboxy-Cyclopropyl-Arg-Gly-Trp-NH₂ (SEQ NO:104).

It is also disclosed that Gly of formula (7) through formula (11) may be optionally substituted with Val or Ala. One preferred peptide composition wherein Gly is substituted with Sar in formula (7) is 4-F-Phe-3,4-Dehydro-Pro-Arg-Sar-Trp-NH₂ (SEQ NO:110).

In yet another embodiment of the invention, the peptides are polypeptides including chemical combinations and/or overlapping chemical combinations of any of the small peptides of any of formula (1) through formula (11) described above which may be utilized alone or in combination with other peptides disclosed in this specification to treat patients suffering from depression. The chemical combinations and/or overlapping chemical combinations of the peptides disclosed preferably range from at least about three to at least about ten amino acids. Examples of such combinations include, but are not necessarily limited to, the compositions as follows: 4-F-Phe-cis- or trans-4-OH-Pro-Ile-Gly-Trp-Gly-NH₂ (SEQ ID NO:46); 4-F-Phe-cis or trans-4-OH-Pro-Ile-Gly-Trp-Gly-Trp-NH₂ (SEQ ID NO:47); 4-F-Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-Gly-NH₂ (SEQ ID NO:48); 4-F-Phe-cis- or trans-4-OH-Pro-Leu-Gly-Trp-Gly-Trp-NH₂ (SEQ ID NO:49); Pro-Ile-Gly-Trp-Pro-Ile-Gly-NH₂ ; (SEQ ID NO:50) 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-Gly-NH₂ (SEQ ID NO:51); 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-Trp-Gly-Trp-NH₂ (SEQ ID NO:52); cis- or trans-4-OH-Pro-Ile-Gly-cis- or trans-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:53); 3,4-dehydro-Pro-D-Arg-Gly-3,4-dehydro-Pro-D-Arg-Gly-NH₂ ; 3,4-dehydro-Pro-D-Arg-Gly-Trp-Gly-NH₂ ; and, 3,4-dehydro-Pro-D-Arg-Gly-Trp-Gly-Trp-NH₂.

Especially preferred compositions of the present invention encompass small peptides which show increased higher activity in the Porsolt swim test described within this specification. These small peptides may vary in length, with the preferred peptides being tetrapeptides, pentapeptides, hexapeptides and heptapeptides. The formula for these especially preferred peptides, which are disclosed throughout this specification, may be:

    R.sup.1 -Phe-Pro.sup.1 -AA.sup.2 -AA.sup.3 -NH.sub.2, (SEQ ID NO:121)

for a tetrapeptide, wherein R¹ is preferably a halogen atom, most preferably a fluorine or chlorine atom, a carboxyl group, an amino group or a nitro group, with all modifications preferably at the C4 atom of Phe; Pro¹ is 3,4-dehydro Pro, Homo-Pro, cis- or trans-4OH-Pro or Pro, as listed in order of preference, AA² is preferably Ile, Leu or Arg; and AA³ is preferably Gly or Trp.

Another preferred tetrapeptide of the present invention is Pro-Ile-Gly-Trp (SEQ ID NO:3).

The formula for the especially preferred pentapeptides, hexapeptides and heptapeptides, which are also disclosed throughout this specification, may be:

    R.sup.1 -Phe-Pro-AA.sup.1 -Gly-AA.sub.(n) -AA.sup.3 -NH.sub.2,

wherein R¹ is preferably a halogen atom, preferably a fluorine or chlorine atom, a carboxyl group, an amino group or a nitro group, with all modifications preferably at the C4 atom of Phe; Pro¹ is 3,4-dehydro Pro, Homo-Pro, cis- or trans-4OH-Pro or Pro, as listed in order of preference, AA² is preferably Arg, Ile, Leu or His, with Arg being especially preferred; AA.sub.(n) is 0-2 amino acid residues, if n=1, then Gly is preferred and if n=2, then Ile-Gly, Ile-Ile or Gly-Gly is preferred; AA³ is preferably Trp or Gly, with Trp most preferred.

The present invention further discloses admixtures of the peptides of formula (1) through formula (11) with known antidepressant compounds such as amitriptyline, fluoxetine (Prozac) and sertraline (Zoloft). It is within the ordinary skill of the artisan to generate various admixtures with the small peptides of the present invention beyond the exemplifications disclosed throughout this specification.

The small peptides with which this invention is concerned are readily prepared by conventional procedures (i.e., carbodiimide method, mixed anhydride method, N, N-carbonyldiimidazole method) for the step-wise synthesis of polypeptides, and also including solid phase peptide synthesis. The substituents groups are also readily added to the polypeptide residues by conventional procedures.

The small peptides of the invention possess antidepressant activity as determined by the Porsolt swim test as described in the Example Section. The Porsolt swim test is based on the observation that when a rat is forced to swim in a situation from which there is no escape, the rat ceases to move altogether and makes only those movements necessary to keep its head above water. Immobility indicates a state of despair. Therefore, a compound with activity as an antidepressant will delay the onset of immobility.

The active ingredient, which may comprise one or more of the peptides disclosed in the present invention, should be formulated in a suitable pharmaceutical carrier for in vivo administration to the patient, by any standard method known in the art. Appropriate routes of administration include, but are not limited to, oral (mouth or peroral administration), sublingual, parenteral (e.g., intravenous, intraspinal, intrathecal, intraventricular, epidermal, intracisternal, intracutaneous or intradermal, subcutaneous, or intramuscular), epicutaneous or transdermal, intranasal or rectal as well as inhalation (poly or mircodispersed aerosol).

As with other pharmaceutical delivery strategies, the primary dosage form depends on the mode of administration. Oral administration includes, but is not limited to tablets, capsules, solutions, suspensions, gels, powders, elixirs or syrups. Sublingual administration includes but is not limited to tablets or lozenges. Parenteral administration includes but is not limited to solutions and suspensions. Epicutaneous or transdermal application will include, but are not necessarily limited to, ointments, creams, pastes, plasters, powders, aerosols, lotions, transdermal patches, discs and solutions. Intranasal administration of the peptide or peptides of the present invention include, but are not limited to, solutions, sprays, inhalants or ointments. Rectal administration may include, but is not necessarily limited to, solutions, ointments or suppositories. The active ingredient may also be formulated for incorporation into liposomes, microcapsules, polymer or wax-based and controlled release preparations. For additional guidance regarding routes of administration and the generation of pharmaceutically effective dose rates, see Chapter 3--"Dosage Form Design: Biopharmaceutical Considerations" in Pharmaceutical Dosage Forms arid Drug Delivery Systems, 1990, Ansel, H. C. and Popovich, N. G., Fifth Ed.; Lea and Febiger, Philadelphia.

The concentration of the peptide(s) used in any of the aforementioned formulations will depend upon the effective dose and the mode of administration used to elicit the appropriate biological effect. The dose should be sufficient to achieve circulating plasma concentrations of the active ingredient such that effective amounts cross the blood-brain barrier that are efficacious. For example, when the tetrapeptide Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:5) is the active ingredient, a circulating plasma level from about 30 mg to about 90 mg per average adult may be used; preferably about 60 mg per average adult. Effective doses for various routes of administration may be extrapolated from dose-response curves derived from in vitro or animal model test systems.

The invention will be further clarified by a consideration of the following examples, which are intended to be purely exemplary of the synthesis and use of the small peptides of the invention.

7. EXAMPLE: A TRI- TETRA- OR PENTA- PEPTIDE AS AN ANTIDEPRESSANT

7.1. MATERIALS AND METHODS

7.1.1. PEPTIDE SYNTHESIS

Small peptides of the present invention were synthesized by methods known to one of ordinary skill in the art. Briefly, 5 mM of Rink amide resin is placed in a reaction vessel of an Applied Biosystem 431A peptide synthesizer. Double couple cycles were used since the amount of starting resin was twice that of a standard run. The following steps were then carried out: (1) the Fmoc blocking group on the resin was first removed by washing with 20% piperidine; (2) the resin is then washed with N-methyl-pyrrolidinone; (3) 2 mM Fmoc-proline was added to the reaction vessel together with 0.45 mM 2-(1H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluronium hexafluorophosphate in a solution of 1-hydroxybenzotriazole and 1 mM of diisopropylethylamine; (4) the resin was washed with N-methylpyrrolidinone; (5) the cycle was repeated with Fmoc-leucine, then with Fmoc-glycine and finally with Fmoc-tryptophan; (6) the peptide resin bond was cleaved with the following solution: 0.25 ml ethanedithiol, 0.25 ml H₂ O, and 9.5 ml TFA, with a cleavage time of 3-4 hours; (7) the peptide was then purified by two reverse phase HPLC procedures, the first in 0.1% TFA in water as the eluting solvent and the second using 0.1% TFA in acetonitrile as the eluting solvent.

The purity of synthesized peptides was analyzed using a HP1090L analytical HPLC equipped with a diode ray. A UV trace showing absorption of the peptide from 220 nm to 310 nm was plotted. Molecular weights were verified by mass spectrometry.

The purity of synthesized peptides was analyzed using a HP1090L analytical HPLC equipped with a diode ray. A UV trace showing absorption of the peptide from 220 nm to 310 nm was plotted. Molecular weights were verified by mass spectrometry.

7.1.2. SYNTHESIS OF PRO-ARG-GLY-NH₂

Pro-Arg-Gly-NH₂ was synthesized manually using a fritted funnel with the step sequence given as for synthesis of Pro-Leu-Gly-Trp-NH₂ (SEQ ID NO:5) and the appropriate Fmoc-amino acids. Regarding synthesis of Pro-Arg-Gly-NH₂, dimethylformamide was used in place of N-methylpyrrolidinone, and in step (6) the peptide resin bond was cleaved using the following solvent mixture: 0.75 g phenol in 0.25 ml thioanisole, 0.5 ml H₂ O and 10 ml TFA.

The other peptides disclosed in this specification, except the tripeptide Pro-Arg-Gly-NH₂, were prepared as, described in Section 6.1.2.

One of ordinary skill in the art could utilize any of a number of known techniques for synthesizing the peptides of the present invention.

Each purified peptide was stored frozen as a white crystalline powder. MIF was also synthesized by techniques known to one of ordinary skill in the art. This tripeptide was stored frozen as a white crystalline powder.

7.1.3. VARIATION OF THE PORSOLT SWIM TEST TO IDENTIFY PEPTIDES WITH ANTIDEPRESSANT ACTIVITY

Male Sprague Dawley rats were obtained from Charles River Laboratories, Wilmington, Mass. The rats were housed individually in stainless steel one half inch wire mesh cages sized in accordance with the "Guide for the Care and Use of Laboratory Animals" of the Institute of Laboratory Animals Resources National Research and Counsel. The animal rooms were kept under a twelve hour light/twelve hour dark cycle, with temperature maintained at 18° to 26° C. and relative humidity at 40% to 70%. The test animals were acclimated for a minimum of seven days prior to initiation of the study. Daily doses of the small peptides of the present invention were prepared by dissolving 1 mg q.s. to 10.0 ml 0.01M acetic acid in 0.9% saline. 1 ml/kg of the respective peptide was then administered by intraperitoneal injection once a day for five consecutive days.

The antidepressant activity of the peptides of the present invention was determined by a variation of the Porsolt swim test (Porsolt, et al., 1977, Nature 266: 730-732). The method is based on the observation that a rat, when forced to swim in a situation from which there is no escape, will, after an initial period of vigorous activity, eventually cease to move altogether and make only those movements necessary to keep its head above water. Immobility indicates a state of despair in which the conditioned rat cannot escape and resigns itself to the experimental situation. On the first day of the study, the animals were plunged individually into a vertical plexiglass cylinder (40 cm in height and 18 cm in diameter) containing 24 cm of water maintained at 25-26° C. The cylinder was painted white. The water was changed between each rat. After 15 minutes in the cylinder the rats were removed and returned to their individual cages without being dried. One hour later the rats were administered the tetrapeptide, MIF or a control (0.01M acetic acid in 0.9% saline), based on individual body weight. On days 2, 3, and 4, at the time of day that corresponds to the average injection time of the entire study group of animals, the rats were injected with either peptide 1-39 or the control solution. On day 5, after being weighed each individual rat was respectively dosed based on individual body weight. Doses were staggered in such a manner as to provide ample time for test evaluation to be conducted between animals. Fifteen minutes following injection, each rat was placed in the water for 300 seconds. The mobile time for each rat was recorded.

7.2. RESULTS

Table 1 and FIGS. 1-3 depict results generated from numerous Porsolt swim tests administered with peptides of the present invention, known antidepressant compounds (e.g., amitriptyline, fluoxetine [Prozac], and sertraline [Zoloft]), known compounds (e.g., Pro-Leu-Gly-NH₂, Pro-D-Leu-Gly-NH₂), and a placebo (CGI: 0.1M acetic acid in 0.9% saline at 1 ml/kg).

The number of responding animals out of a possible 12 animals utilized in each test group is reported in column 4 of Table 1 for all compounds, doses and combinations tested. FIG. 1 provides a graphical analysis of the average number of responding animals out of a possible 12 animals compiled in one or more experimental groups for selected compounds of the present invention, as well as test compounds. More specifically, the data for the following compounds is listed in FIG. 1 as follows:

1. 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:55), corresponding to listing #2 of Table 1;

2. 4-F-Phe-4-OH-Pro-Arg-Gly-Ile-Gly-TRP-NH₂ (SEQ ID NO:56), corresponding to listing #3 of Table 1;

3. 4-F-Phe-4-Homo-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:57), corresponding to listing #4 of Table 1;

4. Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:3), corresponding to listing #5 of Table 1;

5. 4-F-Phe-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:16), corresponding to listing #8 of Table 1;

6. Amitriptyline, corresponding to listing #9 of Table 1;

7. 4-F-Phe-4-OH-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ ID NO:58), corresponding to listing #11 of Table 1;

8. 4-CH30-Phe-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:59), corresponding to listing #12 of Table 1;

9. 4-Cl-Phe-4-OH-Pro-Ile-Gly-NH₂ (SEQ ID NO:60), corresponding to listing #13 of Table 1;

10. 4-F-Phe-4-OH-Pro-Ile-Gly-Trp-NH₂ (SEQ ID NO:41), corresponding to listing #14 of Table 1;

11. 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43), corresponding to listing #17 of Table 1;

12. 4-OH-Pro-Ile-Gly-NH₂, corresponding to listing #20 of Table 1;

13. Zoloft, corresponding to listing #41 of Table 1;

14. Prozac, corresponding to listing #48 of Table 1; and

15. Pro-Leu-Gly-NH₂, corresponding to listing #55 of Table 1.

Compounds #1-15 listed above also correspond to the graphical data presented in FIG. 2 and FIG. 3.

Compound designations are for reference purposes only. The numerical designations utilized in Table 1 do not correspond to data entries as Compound #1-15 in FIG. 1, FIG. 2 and FIG. 3. The data reported in FIGS. 1-3 correspond to tests using the standard 0.1 mg/ml dosage. Data presented in Table 1 lists this data as well as numerous additional tests with other peptides of the present invention, various combinations of compounds and at varying dosages.

A responding animal is defined as an animal whose mobile time during the 300 second exposure to the water tank was of longer duration than the average mobile time of the CGI group plus one standard deviation. For example, if the average mobile time for CGI group of twelve treated rats is 35 seconds plus or minus one standard deviation of 15 seconds, then a responding animal is defined as an animal exhibiting a mobile time greater than fifty seconds. Therefore, the control group mean plus one standard deviation was taken as a threshold for response; the number of rats with mobile times exceeding this level is tabulated as a responding animal.

Table 1 (column 5) gives the difference between the mobile times of the various compounds, combination of compounds and dosages tested and the mobile time of CGI. The average of mean mobile time for each peptide are presented. The average mean mobile time between experimental groups for each compound listed above as Compound #1-15, represented by a double asterisk, is also presented as part of FIG. 2. FIG. 2 illustrates the mean of mobile time for peptides identified above as compounds #1-15. The treatment means were compared with control (CGI) means by a one-tailed Student's t-test. The probabilities so obtained are given in Table 1 (column 8) for the all compounds tested.

The Z-score of for mean of mobile time for Compound #1-15, again as listed above, is reported in FIG. 3 and Table 1 (at column 10). The Z-score is a dimensionless measure of efficacy that was averaged over the numerous studies. The mean of Z-score is defined as the difference between the treatment group's mean mobile time and the control group's mean mobile time, divided by the standard deviation of the mean mobile time of the control group. Therefore, an inefficacious compound will generate a Z-score near zero, and higher Z-scores denote increasing efficacy.

Data presented in Table 1 and the graphic representation of data listed above as compounds #1-15 in FIGS. 1-3 indicate that numerous peptides of the present invention exhibit antidepressant activity in comparison to known antidepressant compounds such as amitriptyline, Prozac and Zoloft. Additionally, the vast majority of the exemplified peptides of the present invention show greater activity than MIF. The present data also indicates that a synergistic effect may exist between peptides of the present invention and known antidepressant compounds, such as Prozac. For example, data presented in Table 1 at No. 1 indicate that an admixture of 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43) at 0.1 mg/ml and prozac at 0.8 mg/ml results in 12 of 12 responders. Additionally, data presented in Table 1 at No. 6 indicate that an admixture of 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-NH₂ (SEQ ID NO:43) at 0.1 mg/ml and amitriptyline results in 10 of 12 responders.

Therefore, Applicants disclose a number of small peptides for use as antidepressant compounds, with biological data to support such use.

Other embodiments of the invention will be apparent to those persons skilled in the art from a consideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention to which exclusive rights are claimed being assessed by the appended claims.

                                      TABLE I                                      __________________________________________________________________________                                Diff.                                                   No. No. of Between Means Outliers Probability of t-Test Z-Score for                           Data-                                                                             Respond-                                                                            of Mobile Time                                                                             Drug                                                                               Diff. for Mobile Time                                                                    Mean of Mobile Time                                                             NO. Structure set                                                             ers for Drug & CGI                                                             CGI Group Between                                                              Drug & CGI for Drug                                                            vs. CGI                     1 2 3 4 5 6 7 8 9                                                            __________________________________________________________________________      1 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-                                                                  63 12   50.49    1  --  0.0005*   3.38                         NH.sub.2  12**** 50.49**    3.38***                                            (SEQ ID NO:43) +                                                               Prozac                                                                         2 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly- 67 11 43 -- -- 0.0002* 4.38                                                                     Trp-NH.sub.2 68 10                                                           33.58 -- -- 0.0000*                                                            3.03                         (SEQ ID NO:55) 69 11 31.42 -- -- 0.000* 3.03                                    71 12 20.92 -- -- 0.000* 3.20                                                   11**** 32.23*    3.41***                                                     3 4-F-Phe-4-OH-Pro-Arg-Gly-IIe-Gly- 71 11 25.09 -- -- 0.0001* 3.84                                                                 Trp-NH.sub.2                                                                 11**** 25.09** -- --                                                            3.84***                     (SEQ ID NO:56)                                                                 4 4-F-Phe-4-HomoPro-Arg-Gly-Trp- 67 11 31.00 -- -- 0.0000* 3.16                                                                    NH.sub.2 68  9                                                               22.83 -- -- 0.0011*                                                            2.06                         (SEQ ID NO:57) 69 11 36.75 -- -- 0.0001* 3.55                                    10.33*** 30.19**    2.92***                                                  5 Pro-Ile-Gly-Trp-NH.sub.2 32 12 41.75 -- -- 0.0000* 3.71                      (SEQ ID NO:3) 33 11 24.59 -- -- 0.0001* 2.06                                    35  7 29.50 -- -- 0.0046* 2.19                                                 39 11 27.17 -- -- 0.0001* 2.20                                                  10.25**** 30.79**    2.54***                                                 6 4-F-Phe-4-OH-Pro-Arg-Gly-Trp- 65 10 92.92 -- -- 0.0008* 3.8l                                                                     NH.sub.2  10****                                                             92.92**    3.81***                                                               (SEQ ID NO:43) +                                                               Amitriptyline                                                                  7 Dose 0.7 mg/kg                                                             49 l1 46.33                                                                    0.0001* 4.85                                                                     4-F-Phe-4-OH-Pro-Ar                                                          g-Gly-Trp- 52  9                                                               18.67 -- -- 0.0033*                                                            4.53                         NH.sub.2  10**** 32.50**    4.69***                                            (SEQ ID NO:43)                                                                 8 4-F-Phe-4-OH-Pro-IIe-Gly-NH.sub.2 33  9 24.00 -- -- 0.0014* 1.67                                                                 (SEQ ID NO:16) 37                                                            12 31.58 -- --                                                                 0.0002* 4.40                                                                      38 12 23.08 -- --                                                           0.0000* 3.44                                                                      39  8 20.08 -- --                                                           0.0029* 1.62                                                                      48  9 16.75                                                                 0.0002* 1.57                                                                       10**** 23.10**                                                              2.54***                     9 Amitriptyline 1 11 76.83 1 1 0.0001* 2.78                                     2 12 54.50 1 -- 0.0005* 4.10                                                   3  8 33.58 1 -- 0.0016* 1.88                                                   4 10 40.08 1 -- 0.0003* 2.24                                                   5  9 70.58 -- -- 0.0002* 7.36                                                  6 11 60.92 1 -- 0.0000* 3.09                                                   7  9 56.92 1 -- 0.0081* 3.01                                                   10  3 12.92 1 1 0.3581 0.43                                                    14  8 56.00 -- -- 0.0081* 1.87                                                 54 10 50.73 1 -- 0.0255* 5.31                                                  55 11 *46.56   0.000* 4.41                                                     65  9 49.25   0.0017* 2.02                                                       9.25**** 50.74**    3.20***                                                10 Dose 0.5 mg\kg 49 10 37.42   0.0001* 3.91                          4-F-Phe-4-OH-Pro-Arg-Gly-Trp- 52  8 15.25 -- -- 0.0025* 2.89                   NH.sub.2   9**** 26.34**    3.4***                                             (SEQ ID NO:43)                                                                11 4-F-Phe-4-OH-Pro-Arg-Gly-Gly- 70  9 23.09 -- -- 0.0008* 1.69                                                                     Trp-NH.sub.2                                                                 9**** 23.09**                                                                  1.69***                      (SEQ ID NO:58)                                                                12 4-CH.sub.3 O-Phe-4-OH-Pro-Arg-Gly- 70  9 21.5 -- -- 0.0073* 1.58                                                                 Trp-NH.sub.2                                                                 9**** 21.5**                                                                   1.58***                      (SEQ ID NO:59)                                                                13 4-Cl-Phe-4-OH-Pro-I1e-Gly-NH.sub.2 44  9 13.67 -- -- 0.0038* 1.88                                                                (SEQ ID NO:60)                                                               9**** 13.67**                                                                  1.88***                     14 4-F-Phe-4-OH-Pro-Ile-Gly-Trp-NH.sub.2 40 11 33.25 -- -- 0.0001* 3.73         (SEQ ID NO:41) 41 11 35.83 -- -- 0.0001* 4.11                                   43  4 10.75 -- -- 0.0125* 1.00                                                 44  9 23.17 -- -- 0.0003* 3.19                                                   8.75**** 25.75**    3.01***                                                15 3,4-Dehydro-Pro-D-Arg-Gly-NH.sub.2 35  9 30.00 -- -- 0.0052* 2.16                                                                 37 11 46.08 -- 1                                                            0.0037* 6.42                                                                      38  6 8.17** --                                                             -- 0.1179 1.22                                                                      8.67****                                                                  28.08**    3.27***                                                              16 4-F-Phe-4-OH-Pro-                                                          Leu-Gly-NH.sub.2 34                                                            10 29.83 -- --                                                                 0.0002* 2.12                                                                     (SEQ ID NO:15)                                                                 35      8                                                                     24.00          --                                                             --       0.0006*                                                                       1.73                                                                      36  8 27.67 -- --                                                           0.0009* 1.60                                                                        8.67****                                                                  27.17**    1.82***                                                              17 4-F-Phe-4-OH-Pro-                                                          Arg-Gly-Trp- 40 12                                                             43.50 -- -- 0.0001*                                                            4.88                         NH.sub.2 41 12 56.75 -- -- 0.0001* 6.51                                        (SEQ ID NO:43) 42  6 24.58 -- -- 0.0019* 1.47                                   43  8 26.50 -- -- 0.0003* 2.50                                                 44 10 23.50 -- -- 0.0034* 3.23                                                 45  9 15.85 -- -- 0.0003* 2.28                                                 46  8 23.83 -- -- 0.0052* 1.47                                                 47       10            15.0   0.0007* 1.97                                     48 10 25.58   0.0000* 2.39                                                     48 10 23.0   0.0001* 2.15                                                      54  7 34.23 1 -- 0.024 3.58                                                    55  4 17.31 -- -- 0.049 1.64                                                   59  8 33.07 1 -- 0.0018* 1.47                                                  60  5 29.34 -- -- 0.253 2.29                                                   63  4 10.82 1 1 0.1268 0.72                                                      8.2*** 26.86**    2.57****                                                 18 Dose 0.2 mg/kg 64  8 34.86 -- 1 0.0009* 1.407                                4-F-Phe-4-OH-Pro-Arg-Gly-Trp-   8**** 34.86**     1.407***                     NH.sub.2                                                                       (SEQ ID NO:43) +                                                               Prozac                                                                        19 Dose 0.6 mg/kg 62  8 24.92 -- -- 0.003* 2.21                                 4-F-Phe-4-OH-Pro-Arg-Gly-Trp-   8**** 24.92** --   2.21***                     NH.sub.2                                                                       (SEQ ID NO:43)                                                                20 4-OH-Pro-Ile-Gly-NH.sub.2 33  8 30.25 -- -- 0.0078* 2.11                      38  8 14.08 -- -- 0.0107* 2.10                                                   8**** 22.17**    2.10***                                                   21 4-OH-Pro-D-Arg-Gly-Trp-NH.sub.2 32  8 18.41 -- -- 0.0011* 1.63                                                                    37  9 22.17 -- --                                                           0.0041* 3.09                                                                      39  7 15.50 -- --                                                           0.0156* 1.26                                                                        8**** 18.69**                                                              1.99***                    22 4-Cl-Phe-4-OH-Pro-Arg-G1y-Trp- 71  8 15.17 -- -- 0.0611 2.32                                                                     NH.sub.2   8****                                                             15.17**    2.32***                                                               (SEQ ID NO:61)                                                                23 Dose 0.2 mg/kg                                                             55  8 24.0 1 1                                                                 0.0347* 2.27                                                                     4-F-Phe-4-OH-Pro-Ar                                                          g-Gly-Trp- 59  7                                                               33.07 1 -- 0.0059*                                                             1.47                         NH.sub.2 60  6 8.00   0.2473 0.62                                              (SEQ ID NO:43) 61  5 12.94 -- 1 0.13 0.709                                      62 11 40.0 -- -- 0.0003* 3.555                                                 63 11 29.99 -- --  0.0001* 2.00736                                             64  8 48.92 -- -- 0.0017* 1.97                                                 65  8 34.25 -- -- 0.003* 1.404                                                 66  6 21.03 -- 1 0.0039* 1.43                                                  69  9 16.25 -- -- 0.0215 1.57                                                    7.9**** 26.84**    1.70***                                                 24 4-OH-Pro-D-Arg-Gly-NH.sub.2 30  6 18.25 -- 1     0.0181*                                                                        1.30                         31 11 43.75 1 -- 0.0001* 3.52                                                  32 10 36.16 -- -- 0.0001* 3.21                                                 36  3 6.67 -- -- 0.2953 0.39                                                     7.5**** 26.21**    2.10***                                                 25 Dose 0.3 mg/kg 49 10 22.75   0.0002* 2.38                                    4-F-Phe-4-OH-Pro-Arg-Gly-Trp- 52  9 12.25 -- -- 0.0067 2.89                    NH.sub.2 54  8 11.73 1 -- 0.044 1.22                                           (SEQ ID NO:43) 59  6 22.82 1 -- 0.0092 1.02                                     60  9 29.34 -- -- 0.0005 2.29                                                  61  2 0.92 -- -- 0.9103 0.0504                                                   7.33**** 19.78**    1.64***                                                26 4-F-Phe-Pro-Leu-Gly-Trp-NH.sub.2 28 10 33.00 -- -- 0.0011* 2.94                                                                  (SEQ ID NO:12) 30                                                            6 17.16 -- --                                                                  0.0170* 1.22                                                                      31  6 14.00 1 --                                                            --  0.0172*                     7.3**** 26.21**    2.10***                                                 27 4-F-Phe-4-OH-Pro-Arg-Gly-Trp- 66  7 41.4 -- 1 0.0008* 2.82                   NH.sub.2   7**** 41.4**    2.82****                                            (SEQ ID NO:43) +                                                               Zoloft                                                                        28 4-F-Phe-4-OH-Pro-Leu-G1y-Trp- 40 10 27.00 -- -- 0.0016* 3.03                                                                     NH.sub.2 42  4                                                               15.83 -- -- 0.0283*                                                            0.95                         (SEQ ID NO:42)   7.0**** 21.42**    1.99***                                   29 3,4-Dehydro-Pro-Arg-Gly-Trp-NH.sub.2 45 10 16.75 -- -- 0.0004* 2.42                                                              (SEQ ID NO:62) 46                                                            4 16.50 -- -- 0.1015                                                           1.02                            7.0**** 16.62**    1.72***                                                 30 Pro-D-Leu-Gly-NH.sub.2 34  7 15.00 -- -- 0.0667 1.07                            7**** 15.00**    1.07***                                                   31 3,4-Dehydro-Pro-D-Arg-Gly-Trp- 42  6 16.41 -- -- 0.0036* 0.98                                                                    NH.sub.2   6****                                                             16.41**    0.98***                                                              32 Pro-Leu-Sar-NH.su                                                          b.2 29  6 15.41 1 --                                                           0.0585 0.95                     6**** 15.41**    0.95***                                                   33 4-NH.sub.2 -Phe-4-OH-Pro-Arg-Gly-Trp- 67  6 15.33 -- -- 0.0236* 1.56         NH.sub.2   6**** 15.33**    1.56****                                          34 4-F-Phe-4-OH-Pro-His-Gly-Trp- 68  6 15.75 -- -- 0.0343 1.42                  NH.sub.2   6**** l5.75**    1.42***                                            (SEQ ID NO:64)                                                                35 4-F-Phe-4-OH-Pro-D-Arg-Gly-Trp- 41  9 17.58 -- -- 0.0020* 2.02                                                                   NH.sub.2 45  6                                                               10.50 -- -- 0.0630                                                             1.51                          46  3 11.42 -- -- 0.1729 0.70                                                    6**** 13.17**    1.41***                                                   36 Tyr-Pro-Trp-Gly-Trp-NH.sub.2 28  6 9.92 -- -- 0.0582 0.88                    (SEQ ID NO:39)   6**** 9.92**    0.88***                                      37 4-OH-Pro-Arg-Gly-NH.sub.2 27  4 28.58 -- -- 0.0308* 1.28                      29  7 25.83 1 -- 0.0038* 1.59                                                    5.5**** 27.2l**    1.43***                                                 38 Pro-D-Arg-Gly-NH.sub.2 20  6 24.92 -- -- 0.0337* 1.30                         21  7 21.92 -- -- 0.0057* 1.67                                                 26  7 28.50 -- -- 0.0034* 1.15                                                 29  2 3.83 1 -- 0.5546 0.24                                                      5.5**** 19.79**    1.09***                                                 39 4-OH-Pro-Trp-Gly-NH.sub.2 28 10 4l.98 -- 1 0.0097* 3.74                       30  1 -4.34 -- -- 0.4195 -0.31                                                  5.5**** 18.82**    1.71***                                                  40 Pro-Arg-Gly-NH.sub.2 18  5 16.83 1 -- 0.0886 0.97                             19  6 31.17 -- -- 0.0280* 1.97                                                 23  5 24.00 -- -- 0.0252* 1.14                                                   5.3**** 24.00**    1.36***                                                 41 Zoloft 20  5 27.67 -- 1 0.0896 1.44                                           21  5 17.17 -- -- 0.0521 1.31                                                  22  6 16.42 -- -- 0.0080* 1.13                                                 23  6 24.92 -- -- 0.0269* 1.18                                                 24  5 20.42 -- 1 0.2057 1.01                                                   66  3 15   0.0958 1.02                                                           5.0**** 20.27**    1.181***                                                42 Pro-Orn-Gly-NH.sub.2 22  5 24.75 -- 1 0.0696 1.71                               5.0**** 24.75**    1.71***                                                 43 4-NO.sub.2 -Phe-4-OH-Pro-Arg-Gly-Trp-  S047  5.0 22.42 1 1 0.0264*                                                             1.28                         NH.sub.2   5.0**** 22.42***    1.28***                                         (SEQ ID NO:65)                                                                44 Pro-Leu-Gly-Trp-NH.sub.2 8  6 39.09 -- -- 0.0727* 2.18                       (SEQ ID NO:5) 12  2 10.25 1 1 0.2553 0.41                                       14  5 20.08 -- -- 0.1268 0.67                                                  17  5 16.25 -- -- 0.0355* 0.86                                                 19  7 18.92 -- -- 0.0243* 1.19                                                 23  5 15.67 -- -- 0.0837 0.74                                                    5.0**** 20.04**    1.01***                                                 45 Dose 0.4 mg\kg 61  5 25.17 -- -- 0.0031* 1.38                      4-F-Phe-4-OH-Pro-D-Arg-Gly-Trp- 62  5 12.09 -- 1  1.07                         NH.sub.2   5**** 18.63** -- --  1.23***                                        (SEQ ID NO:43)                                                                54 4-OH-Pro-Ile-Gly-Trp-NH.sub.2 34  4 12.16 -- -- 0.0732 0.87                  (SEQ ID NO:2)   4.0**** 12.16**    0.87***                                    55 Pro-Leu-Gly-NH.sub.2 2  9 29.25 1 1 0.0041* 2.20                              3  5 10.08 1 -- 0.1618 0.56                                                    4  4 13.92 1 -- 0.0716 0.78                                                    5  5 17.33 -- 1 0.0815 1.82                                                    6  4 15.67 1 -- 0.1011 0.79                                                    7  6 16.16 1 -- 0.0561 0.85                                                    8  3 1.25 -- -- 0.8735 0.07                                                    9  0 1.00 -- -- 0.8356 0.07                                                    10  1 9.00 1 1 0.3794 0.30                                                     11  1 -3.67 -- -- 0.6486 -0.15                                                 12  2 9.17 1 1 0.3839 0.37                                                     14  4 16.75 -- -- 0.1553 0.56                                                  15  7 45.75 -- -- 0.0047* 1.42                                                 16  2 2.00 -- -- 0.7974 0.10                                                   20  6 22.84 -- -- 0.0337* 1.19                                                   3.93**** 13.77**    0.73***                                                56 4-F-Phe-4-OH-Pro-Arg-Ile-Gly-Trp 70  3 9.09   0.1077* 0.6679                                                                     (SEQ ID NO:67)                                                               3**** 9.09**                                                                   0.6679***                   57 Cis-4-OH-Pro-D-Arg-Gly-NH.sub.2 43  3 9.08 -- -- 0.0286* 0.85                                                                       3**** 9.08**                                                              0.85***                     58 4-Thio-Pro-Leu-Gly-NH.sub.2 27  3 5.00 -- -- 0.6084 0.22                        3**** 5.00**    0.22***                                                    59 Pro-Trp-Gly-Trp-NH.sub.2 24  3 7.5 -- -- 0.4767 0.37                         (SEQ ID NO:8)   3**** 7.5** -- --  0.37***                                    46 4-OH-Pro-Leu-Gly-Trp-NH.sub.2 26  6 33.83 -- -- 0.0059* 1.37                                                                     (SEQ ID NO:1) 31                                                             3 4.25 1 -- 0.3288                                                             0.34                            4.5**** 19.04**    0.86***                                                 47 Phe-Pro-Leu-Gly-NH.sub.2 9  6 11.33 -- -- 0.0931 0.77                        (SEQ ID NO:11) 13  3 20.67 -- 1 0.3057 0.76                                       4.5**** 16.00**    0.76***                                                 48 Prozac 16  6 21.42 -- -- 0.0282* 1.11                                         17  3 19.08 -- -- 0.0397* 1.01                                                 18  4 11.75 1 -- 0.1020 0.68                                                   19  6 18.09 -- -- 0.0200* 1.14                                                 25  5 24.25 -- -- 0.0389* 1.50                                                 64  2 6   0.4999 0.2422                                                          4.33**** 16.77**    0.947***                                               49 Pro-Arg-Ala-NH.sub.2 21  4 18.58 -- -- 0.0268* 1.42                             4**** 18.58**    1.42***                                                   50 3-F-Phe-4-OH-Pro-Arg-Gly-Trp- S047  4 18.55 1 1 0.0484 1.06                  NH.sub.2   4**** 18.55**    1.06***                                            (SEQ ID NO:66)                                                                51 Pro-Trp-Gly-NH.sub.2 5  5 19.34 -- -- 0.0956 2.02                             13  4 17.42 -- -- 0.1218 0.64                                                  18  3 14.75 -- -- 0.1570 0.85                                                    4.0**** 17.17**    1.17***                                                 52 Pro-Arg-Gly-Trp-NH.sub.2 24  4 18.5 -- -- 0.0529 0.91                        (SEQ ID NO:7)   4.0**** 18.5** -- --  0.91***                                 53 Pro-D-Arg-Gly-Trp-NH.sub.2 27  4 19.33 -- -- 0.0754 0.86                        4.0**** 19.33**    0.86***                                                 60 Trp-Pro-Leu-Gly-NH.sub.2 8  3 3.84 -- -- 0.5805 0.21                         (SEQ ID NO:17)   3**** 3.84**    0.21***                                      61 Pro-Leu-Gly-Tyr-NH.sub.2 7  3 15.83 1 -- 0.0741 0.84                         (SEQ ID NO:6) 13  0 -5.5 -- -- 0.5387 -0.20                                     25  4 8.75 -- 1 0.3790 0.54                                                      2.33**** 6.36**    0.38***                                                 62 Tyr-Pro-Leu-Gly-Trp-NH.sub.2 26  2 10.58 -- -- 0.3093 0.43                   (SEQ ID NO:32)   2**** 10.58**    0.43***                                     63 Pro-Ile-Gly-NH.sub.2 36  2 9.42 -- -- 0.1128 0.55                               2**** 9.42**    0.55***                                                    64 2-F-Phe-4-OH-Pro-Arg-Gly-Trp- S047  2 6.27 1 1 0.409 0.36                    NH.sub.2   2**** 6.27**    0.36***                                             (SEQ ID NO:68)   2**** 6.27**    0.36***                                      65 Tyr-Tyr-Pro-Leu-Gly-NH.sub.2 9  2 5.25 -- -- 0.3621 0.35                     (SEQ ID NO:27)   2**** 5.25**    0.35***                                      66 Phe-Tyr-Pro-Leu-Gly-NH.sub.2 15  1 5.58 -- -- 0.6212 0.17                    (SEQ ID NO:23)   1.0**** 5.58**    0.17***                                    67 Pro-Lys-Gly-NH.sub.2 17  1 6.25 -- -- 0.3400 0.33                               1.0**** 6.25**    0.33***                                                  68 Pro-Orn-Tyr-NH.sub.2 22  1 -1.25 -- -- 0.8344 -0.09                             1**** -1.25**    -0.09***                                                  69 Pro-Trp-Gly 11  0 -4.42 -- -- 0.5718 -0.18                                      0**** -4.42** -- --  -0.18***                                              70 Dose 0.01 mg/kg 47  0 -4.75   0.1237 -0.62                                   4-F-Phe-4-OH-Pro-Arg-Gly-Trp-   0**** -4.75**    -0.62***                      NH.sub.2                                                                       (SEQ ID NO:43)                                                              __________________________________________________________________________      Comments:                                                                      a. Tests were run on 12 rats per group and unless otherwise stated, doses      are 0.1 mg/kg.                                                                 b. CGI: Control group inactive                                                 c. Mobile time = seconds struggling                                            d. Outliers: Mobile time is over 4 standard deviation                          e. Number of Responders: Number of rats in the Drug Group with Mobile Tim      > (Mean plus Standard Deviation of Control Group)                              f. Difference between Drug & CGI = (Mobile Time of Drug Group minus            Control Mobile Time), in seconds                                               g. Student's tTest-statistical procedure to determine significant              difference between the means of two independent samples (Drug & CGI)           h. ZScore = (Mobile Time of Drug Group minus Control Mobile Time)/(Contro      Standard Deviation)                                                            i. *significant difference for onetailed tTest                                 j. **Average of mean Mobile Time (Drug vs CGI)                                 k. ***Average of mean ZScore (Drug vs CGI)                                     l. ****Average of Number of Responders                                   

    __________________________________________________________________________     #             SEQUENCE LISTING                                                    - -  - - (1) GENERAL INFORMATION:                                              - -    (iii) NUMBER OF SEQUENCES: 128                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 1:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #1 is either cis- or trans- -           #4Hyp"                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -         (xi) SEQUENCE DESCRIPTION: SEQ - #ID NO: 1:                        - -      Xaa Leu Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 2:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #1 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"Amino acid #4 is a modified Trp residue: -         #an amine                                                                                       group rep - #laces a hydroxyl group at the carboxy            terminus."                                                                        - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #2:                            - -      Xaa Ile Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 3:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hyroxyl g - #roup at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #3:                            - -      Pro Ile Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 4:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with a C3=C4 double bond."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amide group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #4:                            - -      Xaa Ile Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 5:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #5:                            - -      Pro Leu Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 6:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Tyr-NH2                                           /note= - #"A modified Tyr residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #6:                            - -      Pro Leu Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 7:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #7:                            - -      Pro Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 8:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #8:                            - -      Pro Trp Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 9:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Tyr-NH2                                           /note= - #"A modified Tyr residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #9:                            - -      Pro Ile Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 10:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #10:                           - -      Trp Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 11:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #11:                           - -      Phe Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 12:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #12:                           - -      Xaa Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 13:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Cl-Phe                                           /note= - #"Phe residue modified at C4 with a chlorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #13:                           - -      Xaa Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 14:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #14:                           - -      Xaa Pro Ile Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 15:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #15:                           - -      Xaa Xaa Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 16:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #16:                           - -      Xaa Xaa Ile Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 17:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #17:                           - -      Trp Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 18:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #18:                           - -      Trp Pro Ile Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 19:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #19:                           - -      Trp Xaa Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 20:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #20:                           - -      Trp Xaa Ile Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 21:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe modified at C4 with a fluorine atom."            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #21:                           - -      Xaa Tyr Pro Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 22:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Cl-Phe                                           /note= - #"Phe residue modified at C4 with a chlorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #22:                           - -      Xaa Tyr Pro Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 23:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #23:                           - -      Phe Tyr Pro Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 24:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #24:                           - -      Phe Tyr Pro Ile Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 25:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #3 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #25:                           - -      Phe Tyr Xaa Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 26:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #3 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #26:                           - -      Phe Tyr Xaa Ile Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 27:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at carboxy terminus."                          - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #27:                           - -      Tyr Tyr Pro Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 28:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #28:                           - -      Tyr Tyr Pro Ile Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 29:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #3 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #29:                           - -      Tyr Tyr Xaa Leu Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 30:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #3 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #30:                           - -      Tyr Tyr Xaa Ile Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 31:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #31:                           - -      Phe Pro Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 32:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #32:                           - -      Tyr Pro Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 33:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #33:                           - -      Phe Xaa Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 34:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #34:                           - -      Phe Pro Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 35:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #35:                           - -      Phe Xaa Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 36:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #36:                           - -      Tyr Xaa Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 37:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #37:                           - -      Tyr Pro Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 38:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #38:                           - -      Tyr Xaa Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 39:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #39:                           - -      Tyr Pro Trp Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 40:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #40:                           - -      Tyr Xaa Trp Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 41:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #41:                           - -      Xaa Xaa Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 42:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #42:                           - -      Xaa Xaa Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 43:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #43:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 44:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #44:                           - -      Pro Ile Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 45:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #1 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #45:                           - -      Xaa Ile Leu Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 46:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"A amino acid #2 is either cis- or trans - #-       4Hyp."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #46:                           - -      Xaa Xaa Ile Gly Trp Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 47:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:7                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #47:                           - -      Xaa Xaa Ile Gly Trp Gly Xaa                                               1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 48:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #48:                           - -      Xaa Xaa Leu Gly Trp Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 49:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:7                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #49:                           - -      Xaa Xaa Leu Gly Trp Gly Xaa                                               1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 50:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:7                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #50:                           - -      Pro Ile Gly Trp Pro Ile Xaa                                               1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 51:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #51:                           - -      Xaa Xaa Arg Gly Trp Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 52:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:7                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #52:                           - -      Xaa Xaa Arg Gly Trp Gly Xaa                                               1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 53:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #1 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #4 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #53:                           - -      Xaa Ile Gly Xaa Ile Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 54:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #54:                           - -      Tyr Pro Trp Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 55:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with a C3=C4 double bond."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #55:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 56:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:7                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #56:                           - -      Xaa Xaa Arg Gly Ile Gly Xaa                                               1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 57:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= Homo-Pro                                          /note= - #"Amino acid #2 is Homo-Pro."                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #57:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 58:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #58:                           - -      Xaa Xaa Arg Gly Gly Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 59:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4CH3O-Phe                                         /note= - #"Phe residue modified at C4 with a methoxy g -      #roup."                                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -            #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #59:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 60:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Cl-Phe                                           /note= - #"Phe residue modified at C4 with a chlorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #60:                           - -      Xaa Xaa Ile Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 61:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4Cl-Phe                                           /note= - #"Phe residue modified at C4 with a chlorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #61:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 62:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #62:                           - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 63:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4-NH2-Phe                                         /note= - #"Phe residue modified at C4 with an amine gr -       #oup."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #63:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 64:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #64:                           - -      Xaa Xaa His Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 65:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4-NO2-Phe                                         /note= - #"Phe residue modified at C4 with a nitro gro -      #up."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -            #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #65:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 66:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3F-Phe                                            /note= - #"Phe residue modified at C3 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #66:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 67:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #67:                           - -      Xaa Xaa Arg Ile Gly Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 68:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 2F-Phe                                            /note= - #"Phe residue modified at C2 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #68:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 69:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= Homo-Pro                                          /note= - #"Amino acid #2 is Homo-Pro."                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #69:                           - -      Xaa Xaa Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 70:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3-3-pyridyl-Ala                                  /note= "- #Ala residue modified at branch methyl group         with - #a                                                                                      pyridyl group - #."                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #70:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 71:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= Homo-Arg                                          /note= - #"Amino acid #3 is Homo-Arg."                           - -     (ix) FEATURE:                                                               (A) NAME/KEY: Modified-site                                                        (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 71:                         - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 72:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with a C3=C4 double bond."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 72:                         - -      Xaa Xaa Ile Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 73:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= L-Allo-Ile                                        /note= - #"Amino acid #3 is L-Allo-Ile."                         - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 73:                         - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 74:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino Acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= Homo-Arg                                          /note= - #"Amino acid #3 is Homo-Arg."                           - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 74:                         - -      Xaa Xaa Xaa Gly Trp                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 75:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom.                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-X                                             /note= - #"A modified Gly residue: a                                           1,2,3,4-Tetr - #ahydroisoquinoline-3-carboxamide              carbamyl                                                                                        group rep - #laces the hydroxyl group at the carboxy                          terminus."                                                       - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 75:                         - -      Xaa Xaa Arg Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 76:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= Dichloro-Phe                                      /note= - #"Phe residue modified at C3 and C4 with a -          #chlorine                                                                                       atom."                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 76:                         - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 77:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4NC-Phe                                           /note= - #"Phe residue modified at C4 with a nitrile g -      #roup."                                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -            #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 77:                         - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 78:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= D-Leu                                             /note= - #"Amino acid #3 is D-Leu."                              - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 78:                         - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 79:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3Hyp                                              /note= - #"Amino acid #2 is trans-3-hydroxy-Pro."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 79:                         - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 80:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 80:                         - -      Xaa Xaa Arg Gly Gly Xaa                                                   1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 81:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4CH3O-Phe                                         /note= - #"Phe residue modified at C4 with a methoxy g -       #roup."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with a C3=C4 double bond."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 81:                         - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 82:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 2-4DiF-Phe                                        /note= - #"Phe residue modified at C2 and C4 with a -          #fluorine                                                                                       atom."                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DiH-Pro                                        /note= - #"A modified proline residue: a double bond is                       replace w - #ith a hydrogen atom at each of C3 and C4."          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - # 82:                         - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 83:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4-CF3-Phe                                         /note= - #"Phe residue modified at C4 with a trifluoro                         methyl gr - #oup."                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."              - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #83:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 84:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (C) OTHER INFORMATION:/lab - #el= 4F-PhenylGly                                      /note= - #"A Gly residue modified at the N-terminus with       - #a                                                                                            phenyl gr - #oup having a fluorine atom at C4.                   - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #84:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 85:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3F-Tyr                                            /note= - #"Tyr residue modified at C3 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #85:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 86:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NHOH                                          /note= - #"A modified Trp residue: a hydroxyamino group                        replaces - #a hydroxyl group at the carboxy terminus."           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #86:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 87:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DiCl-Phe                                       /note= - #"Phe residue modified at C3 and C4 with a -          #chlorine                                                                                       atom."                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DiH-Pro                                        /note= - #"A modified proline residue:  a double bond                         replaced - #with a hydrogen atom at each of C3 and C4."          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #87:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 88:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 2F-Tyr                                            /note= - #"Tyr residue modified at C2 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #88:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 89:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"A proline residue with a C3=C4 double bond. -      #"                                                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 7-AzaTrp-NH2                                      /note= - #"A modified Trp residue: a nitrogen atom replac      - #es                                                                                          C7 and - #an amine group replaces a hydroxyl group at the                      carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #89:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 90:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"A proline residue with a C3=C4 double bond. -      #"                                                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Trp-NH2                                        /note= - #"A modified Trp residue modified at C4 with -        #a                                                                                              fluorine - #atom and with an amine group in place of a                        hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #90:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 91:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"A proline residue with a C3=C4 double bond. -      #"                                                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 5F-Trp-NH2                                        /note= - #"A Trp residue modified at C5 with a fluorin -       #e                                                                                              atom and - #with an amine group replacing a hydroxyl          group                                                                                           at the - #carboxy terminus."                                     - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #91:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 92:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DiH-Pro                                        /note= - #"A modified proline residue: a double bond                          replaced - #by a hydrogen atom at both C3 and C4."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 6F-Trp-NH2                                        /note= - #"A Trp residue modified at C6 with a fluorin -       #e atom                                                                                         and with - #an amine group in place of a hydroxyl group       - #at                                                                                           the carbo - #xy terminus."                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #92:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 93:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with a C3=C4 double bond."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 3-CH3O-Trp-NH2                                    /note= - #"A Trp residue modified at C3 with a methoxy -       # group                                                                                         and with - #an amine group in place of a hydroxyl group       - #at                                                                                           the carbo - #xy terminus."                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #93:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 94:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= N-CH3-Trp-NH2                                     /note= - #"Trp residue modified at the hetero nitrogen wi      - #th                                                                                          a methyl - #group and an amine group replaces a hydroxyl                       group at - #the C-terminu                                               (xi) SEQUENCE DESCRIPTION: SEQ - #ID NO: 94:                            - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 95:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 1-CH3-Trp-NH2                                     /note= - #"A Trp residue modified at C1 with a methyl -        #group                                                                                          and an - #amine group replaces a hydroxly group at the                        carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #95:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 96:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 4-CH3-Trp-NH2                                     /note= - #"A trp residue modified at C4 with a methyl -        #group                                                                                          and an - #amine group replaces a hydroxyl group at the                        carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #96:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 97:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 5-CH3-Trp-NH2                                     /note= - #"A Trp residue modified at C5 with a methyl -        #group                                                                                          and an - #amine group replaces a hydroxyl group at the                        carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #97:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 98:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 6-CH3-Trp-NH2                                     /note= - #"A Trp residue modified at C6 with a methyl -        #group                                                                                          and an - #amine group replaces a hydroxyl group at the                        carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #98:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 99:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 5-OH-Trp-NH2                                      /note= - #"A Trp residue modified at C5 with a hydroxy -       #l                                                                                              group and - # an amine group replaces a hydroxyl group        at - #the                                                                                       carboxy t - #erminus."                                           - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #99:                           - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 100:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe-Acid                                       /note= - #"A Phe residue modified at C4 with a fluorin -      #e atom                                                                                        and isoni - #pecotic acid replaces a hydroxyl group at         the                                                                                             carboxy t - #erminus."                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2-complex                                   /note= - #"A modified Trp residue: an amine group             complex - #ed                                                                                   with 4-py - #ridinecarboxylic acid replaces a hydroxyl        group                                                                                           at the - #carboxy terminus."                                     - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #100:                          - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 101:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4-F-Phe-2CarbA                                    /note= - #"A modified Phe residue with a fluorine atom -      #at C4                                                                                         and with - #a 2-Carboxy Azetidino group in place of a                          hydroxyl - #group at the carboxy terminus."                      - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #101:                          - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 102:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"A modified Phe residue with a fluorine atom -       #at                                                                                             C4."                                                             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AminoAcid                                         /note= - #"Amino acid #2 is 1-Amino-1-Carboxy cyclopentan     e. - #"                                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #102:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 103:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe-CAzi                                       /note= - #"A modified Phe residue with a fluorine atom -       #at C4                                                                                          and a - #2-carboxy Aziridino group in place of a              hydroxyl                                                                                        group at - #the carboxy terminus."                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #103:                          - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 104:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"A modified Phe residue with a fluorine atom -      #at                                                                                            C4."                                                             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AminoAcid                                         /note= - #"Amino acid #2 is 1-Amino-1-carboxy cyclopropane     . - #"                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #104:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 105:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe-CTtpyr                                     /note= - #"A modified Phe residue with a fluorine atom -       #at                                                                                             C4 and - #a 3-Carboxy-1,4,5,6-Tetrahydropyridine in           place                                                                                           of a h - #ydroxyl group at the carboxy terminus."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #105:                          - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 106:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe-Pyrrole                                    /note= - #"A modified Phe residue with a fluorine atom -       #at                                                                                              C4 an - #d a 2-carboxypyrrolyl group in place of a           hydro - #xyl                                                                                     group - #at the carboxy terminus."                              - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #106:                          - -      Xaa Arg Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 107:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Trp-NH2                                        /note= - #"A modified Trp residue with a fluorine atom -      #at                                                                                            C4 and - #an amine group replacing a hydroxyl group at th      - #e                                                                                           carboxy                                                                        terminus."                                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #107:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 108:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4-Hyp                                             /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= 7-CH3-Trp-NH2                                     /note= - #"A modified Trp residue with a methyl group -       #at                                                                                             C7 and - #an amine group in place of a hydroxyl group -       #at                                                                                             the carbo - #xy terminus."                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #108:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 109:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 4Hyp                                              /note= - #"Amino acid #2 is either cis- or trans- -           #4Hyp."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= 5-5-5TriF-Leu                                     /note= - #"Leu residue modified at C5 with three              fluorine                                                                                        atoms."                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #109:                          - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 110:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -       #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Sar                                               /note= - #"Amino acid #4 is L-sarcosine (N-methylglycine).       - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #110:                          - -      Xaa Xaa Arg Xaa Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 111:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= 4F-Phe                                            /note= - #"Phe residue modified at C4 with a fluorine -        #atom."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= 3-4DeH-Pro                                        /note= - #"Proline residue with C3=C4 double bond."             - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Sar                                               /note= - #"Amino acid #4 is L-sarcosine (N-methylglycine).     "                                                                                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #111:                          - -      Xaa Xaa Arg Xaa Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 112:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                       /note= "A modifi - #ed Gly residue: an amine group replaces a                      hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #112:                          - -      Tyr Pro Leu Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 113:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Trp, Tyr or Phe residue modified with a                           hydrogen - #atom; a lower alkyl group; a halogen atom; or      - #a                                                                                           hydroxyl, - #sulphydryl, alkylamino or dialkylamino            group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro or dehydro-Pro residue modified with a                       hydrogen - #atom; a lower alkyl group; a halogen atom; or      - #a                                                                                           hydroxyl, - #sulphydryl, alkylamino or dialkylamino            group."                                                                           - -      FEATURE:                                                                       (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid of the group Leu, Ile and -          #Trp."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-R                                             /note= - #"A Gly residue modified with a carboxyl group,                      a hydroxy - #alkyl group, a carbamyl group, an alkylcarbam     yl                                                                                             group, or - # an alkoxycarbonyl group at the carboxy                           terminus."                                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #113:                          - -      Xaa Xaa Xaa Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 114:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Leu, Ile or Trp residue modified with a                       hydrogen atom; a lo - #wer alkyl group; a halogen; or a            hydroxyl,                                                                                       sulphydryl, - #alkylamino, or dialkylamino group."              - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro or dehydro-Pro residue modified with a                        hydrogen - #atom; a halogen atom; or a lower alkyl,                            hydroxyl, - #sulphydryl, alkylamino, or dialkylamino           group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid of the group Leu, Ile, and -         #Trp,                                                                                           with the - #proviso that AA2 cannot be Trp if the amino       - #acid                                                                                         at locati - #on 1 is a Tyr residue modified with a            hydrog - #en                                                                                    atom and - #the amino acid at location 2 is a Pro residu      - #e                                                                                           modified - #with a hydrogen atom."                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #114:                          - -      Xaa Xaa Xaa Xaa                                                           1                                                                          - -  - - (2)INFORMATION FOR SEQ ID NO: 115:                                    - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Trp, Tyr or Phe residue modified with a                           hydrogen - #atom; a halogen atom; or a lower alkyl,                            hydroxyl, - #sulphydryl, alkylamino or dialkylamino            group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #""R2-Pro1 is a Pro or dehydro-Pro residue mo -      #dified                                                                                        with a - #hydrogen atom; a halogen atom; or a lower alkyl      - #, a                                                                                         hydroxyl, - #sulphydryl, alkylamino, or dialkylamino           group,                                                                                          wherein t - #he N-terminus heterocyclic nitrogen ring of      the                                                                                            Pro or - #dehydro-Pro residue is modified with a cis- or       - #trans                                                                                        -4-OH- gr - #oup."                                               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"A amino acid of the group Leu, Ile, Trp -          #and                                                                                            Ar                                                                  (ix) FEATURE:                                                                        (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-R                                             /note= - #"A Gly residue modified with a carboxyl,                            hydroxyalkyl - #, carbamyl, alkylcarbamyl or alkoxycarbony     l                                                                                              group at - #the carboxy terminus."                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #115:                          - -      Xaa Xaa Xaa Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 116:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe or Tyr residue modified with a hydrog -       #en                                                                                             atom; a - #halogen atom; a lower alkyl, hydroxyl,                             sulphydryl, - #alkylamino, or dialkylamino group."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCN:2                                                                     (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid from the group Phe and Tyr."            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                         /note= "A - #Pro or dehydro-Pro residue modified with a                        hydrogen atom; - #a halogen atom; or a lower alkyl,              hydroxyl,                                                                                     sulphydryl, alkyl - #amino or dialkylamino group."                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= AA3                                               /note= - #"An amino acid from the group of Leu and -           #Ile."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-R                                             /note= - #"A Gly residue modified with a carboxyl,                            hydroxyalkyl - #, carbamyl, alkylcarbamyl or alkoxycarbony     l                                                                                              group at - #the carboxy terminus."                               - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #116:                          - -      Xaa Xaa Xaa Xaa Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 117:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LEN 5 amino acid - #s                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                          /note= "A - #Phe or Tyr residue modified with a hydrogen                       atom; a haloge - #n atom; or a lower alkyl, hydroxyl,            carbamyl,                                                                                     alkylcarbamyl, or - # alkoxycarbonyl group."                       - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid from the group Phe and Tyr."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                         /note= "A - #Pro or dehydro-Pro residue modified with a                        hydrogen atom; - #a halogen atom; or a lower alkyl,              hydroxyl,                                                                                     sulphydryl, alkyl - #amino or dialkylamino group."                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= AA3                                               /note= - #"An amino acid of the group Leu and Ile."              - -     (ix) FEAT                                                                       (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Gly-NH2                                           /note= - #"A modified Gly residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #117:                          - -      Xaa Xaa Xaa Xaa Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 118:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-Pro1                                          /note= "- #A Pro or dehydro-Pro residue modified with a                        hydrogen atom - #; a halogen atom; or a lower alkyl,            hydroxyl,                                                                                      sulphydryl, a - #lkylamino or dialkylamino group."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AA1                                             ote= "An - #amino acid from the group Leu and Ile."                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid from the group Leu and Ile."            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= AA3-R                                             /note= - #"A Trp residue modified at the carboxy terminus                      with a - #carboxyl, hydroxyalkyl, carbamyl, alkylcarbamyl      or                                                                                             alkoxycarbon - #yl group."                                       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #118:                          - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 119:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-Pro1                                           /note= - #"A Pro or dehydro-Pro residue modified with a                        hydrogen - #atom; a halogen atom; or a lower alkyl,                            hydroxyl, - #sulphydryl, alkylamino, or dialkylamino           group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AA1                                               /note= - #"An amino acid from the group Leu and Ile."           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"An amino acid from the group Leu and Ile."            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #119:                          - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 120:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-Phe                                            /note= - #"A Phe residue modified with a halogen atom."          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Arg                                            /note= - #"An Arg residue modified with a carboxylic acid      - # of                                                                                         a monocyc - #lic organic compound with a three to six                          membered - #ring structure having a hetero nitrogen            atom."                                                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #120:                          - -      Xaa Xaa Gly Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 121:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-Phe                                            /note= - #"A Phe residue modified with a halogen atom, -      #a                                                                                             carboxyl - #group, an amino group, or a nitro group."            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= Pro1                                              /note= - #"An amino acid from the group of 3,4-dehydro -       #Pro,                                                                                           Homo-Pro, - #cis- or trans-4-OH-Pro, or Pro."                    - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                              /note= "- #An amino acid from the group of Ile, Leu and -      # Arg."                                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:4                                                                 (D) OTHER INFORMATION:/lab - #el= AA3-NH2                                           /note= - #"A modified Gly or Trp residue: an amine gro -       #up                                                                                             replaces - #a hydroxyl group at the carboxy terminus."          - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #121:                          - -      Xaa Xaa Xaa Xaa                                                           1                                                                          - -  - - (2) INFORMATION FOR SEQ ID NO: 122:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-Phe                                            /note= - #"A Phe residue modified with a halogen atom."          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= AA1                                               /note= - #"An amino acid from the group                                        1-amino-1-ca - #rboxycyclopentane and                                          1-amino-1-ca - #rboxy-cyclopropyl."                              - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group replace      - #s a                                                                                         hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #122:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 123:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe residue modified with hydrogen atom, a                        halogen a - #tom, or a hydroxyl group."                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro residue modified with a hydrogen atom, -      #a                                                                                             halogen a - #tom or a hydroxyl group."                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= AA2                                               /note= - #"The amino acid homo-Arg."                             - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #123:                          - -      Xaa Xaa Xaa Gly Trp                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 124:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                          /note= "A - #Phe, PhenylGly or Tyr residue modified with a                     hydrogen atom; - #at least one halogen atom; or a lower          alkyl,                                                                                        hydroxyl, sulphyd - #ryl, alkylamino, or diakylamino            group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro or dehydro-Pro residue modified with a                       hydrogen - #atom; at least one halogen atom; or a lower                        alkyl, hy - #droxyl, sulphydryl, alkylamino, or diakylamin     o                                                                                              group."                                                          - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= AA3-R                                             /note= - #"A Trp or AzaTrp residue modified with an am -       #ino                                                                                            group or - #a hydroxylamino group."                              - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #124:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 125:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe residue modified with a hydrogen atom,       - #at                                                                                           least one - # halogen atom or a hydroxyl group."                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro residue modified with a hydrogen atom, -      #at                                                                                            least one - # halogen atom or a hydroxyl group."                 - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= R4-Trp-NH2                                        /note= - #"A Trp residue modified at one of C4, C5, - #C6      or C7                                                                                          with a - #halogen atom, a hydroxyl group or an alkyl grou      - #p                                                                                           and modif - #ied at the carboxy terminus where an amine        grou - #p                                                                                       replaces - #a hydroxyl group."                                   - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #125:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 126:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe residue modified with a hydrogen atom,       - #at                                                                                           least one - # halogen atom or a hydroxyl group."                - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro residue modified with a hydrogen atom, -      #at                                                                                            least one - # halogen atom or a hydroxyl group."                 - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:3                                                                 (D) OTHER INFORMATION:/lab - #el= R5-AA2                                            /note= - #"A Leu residue modified with at least one ha -       #logen                                                                                          atom."                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= Trp-NH2                                           /note= - #"A modified Trp residue: an amine group             replace - #s a                                                                                  hydroxyl - #group at the carboxy terminus."                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #126:                          - -      Xaa Xaa Xaa Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 127:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe residue modified with a hydrogen atom -      #or at                                                                                         least one - # halogen atom."                                     - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A Pro or dehydro-Pro residue modified with a                        hydrogen - #atom or at least one halogen atom."                  - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= R4-AA3                                            /note= - #"A Trp residue modified with at least one ha -       #logen,                                                                                         a hydroxy - #l group, a methyl group, or a methoxy            group."                                                                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:5                                                                 (D) OTHER INFORMATION:/lab - #el= AA3-R                                             /note= - #"A Trp residue modified with a carboxyl group,      - #a                                                                                           hydroxyalkyl - # group, a carbamyl group, an alkylcarbamyl                     group, or - # an alkoxycarbonyl group."                          - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #127:                          - -      Xaa Xaa Arg Gly Xaa                                                       1             - #  5                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 128:                                   - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino - #acids                                                   (B) TYPE: amino acid                                                           (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: peptide                                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:1                                                                 (D) OTHER INFORMATION:/lab - #el= R1-AA1                                            /note= - #"A Phe residue modified with a hydrogen atom; -      #a                                                                                             halogen a - #tom; or a lower alkyl, hydroxyl, sulphydryl,                      alkylamino, - #or dialkylamino group."                           - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:2                                                                 (D) OTHER INFORMATION:/lab - #el= R2-Pro1                                           /note= - #"A dehydro-Pro residue modified with a hydrogen                      atom; a - #halogen atom; or a lower alkyl, hydroxyl,                           sulphydryl, - #alkylamino, or dialkylamino group."               - -     (ix) FEATURE:                                                                   (A) NAME/KEY: Modified-sit - #e                                                (B) LOCATION:6                                                                 (D) OTHER INFORMATION:/lab - #el= AA3-R                                             /note= - #"A Trp residue modified with a carboxyl group,       - #a                                                                                            hydoxyalkyl - #group, a carbamyl group, an alkylcarbamyl                      group, or - # an alkoxycarbonyl group."                          - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #128:                          - -      Xaa Xaa Arg Gly Gly Xaa                                                   1             - #  5                                                     __________________________________________________________________________ 

What is claimed is:
 1. A tetrapeptide composition or salt thereof, comprising a general formula ( 5b):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro-AA.sup.2 -Gly-R.sup.3 (SEQ ID NO:115)(5b)

wherein Pro¹ represents Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid Arg; R¹ and R² are each independently selected from the group consisting of a hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms, a halogen atom, a hydroxyl group, a sulphydryl group, an alkylamino group, and a dialkylamino group and R³ is a carbamyl group.
 2. The tetrapeptide of claim 1 which is selected from the group consisting of:4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-1,2,3,4-Tetrahydroisoquinoline-3-carboxamide (SEQ NO:75); and, pharmaceutically acceptable salts thereof.
 3. A pentapeptide composition or salt thereof, comprising a general formula (7b):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp-NH.sub.2( 7b)

wherein Pro¹ represents the amino acid Pro; AA¹ represents the amino acid Phe; AA² represents an amino acid Arg; and R¹ and R² each independently are selected from the group consisting of a hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms, a halogen atom, a hydroxyl group, a sulphydryl group, an alkylamino group, and a dialkylamino group.
 4. A pentapeptide composition or salt thereof, comprising a general formula (7c):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-Trp (SEQ ID NO:123)(7c)

wherein Pro¹ represents the amino acid Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid homo-Arg; and R¹ and R² each independently are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydroxyl group.
 5. The pentapeptide of claim 4 which is selected from the group consisting of:4-F-Phe-cis- or trans-4-OH-Pro-Homo-Arg-Gly-Trp (SEQ NO:74); and, pharmaceutically acceptable salts thereof.
 6. A pentapeptide composition or salt thereof, comprising a general formula (7e):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -Trp-NH.sub.2 (SEQ ID NO:125)                                           (7e)

wherein Pro¹ represents the amino acid Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid Arg; R¹ and R² each independently are selected from the group consisting of a hydrogen atom, at least one halogen atom and a hydroxyl group; and the tryptophan residue is modified at one of C4, C5, C6 and C7 with R⁴ selected from the group consisting of a halogen atom, a hydroxyl group, and an alkyl group.
 7. The pentapeptide of claim 6 selected from the group consisting of:4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:107); 4-F-Phe-cis- or trans-4-OH-Pro-Arg-Gly-7-Methyl-Trp-NH₂ (SEQ NO:108); and, pharmaceutically acceptable salts thereof.
 8. A pentapeptide composition or salt thereof, comprising a general formula (7f):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -R.sup.5 -AA.sup.2 -Gly-Trp-NH.sub.2 (SEQ ID NO:126)                                           (7f)

wherein Pro¹ represents the amino acid Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid Leu; R¹ and R² each independently are selected from the group consisting of a hydrogen atom, at least one halogen atom and a hydroxyl group; and R⁵ represents at least one halogen atom.
 9. The pentapeptide of claim 8 selected from the group consisting of:4-F-Phe-cis- or trans-4-OH-Pro-5,5,5-Trifluoro-Leu-Gly-Trp-NH₂ (SEQ NO:109); and, pharmaceutically acceptable salts thereof.
 10. A pentapeptide composition or salt thereof, comprising a general formula (7g):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -Gly-R.sup.4 -AA.sup.3 -R (SEQ ID NO:127)                                           (7g)

wherein Pro¹ represents an amino acid selected from the group consisting of Pro and Dehydro-Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid Arg; AA³ represents the amino acid Trp; R¹ and R² each independently are selected from the group consisting of a hydrogen atom and at least one halogen atom; R⁴ is selected from the group consisting of at least one halogen atom, a hydroxyl group, a methyl group, and a methoxy group; and R is selected from the group consisting of a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, and an alkoxycarbonyl group.
 11. The pentapeptide of claim 10 selected from the group consisting of:4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-F-Trp-NH₂ (SEQ NO:90); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-F-Trp-NH₂ (SEQ NO:91); 4-F-Phe-3,4-Dihydro-Pro-Arg-Gly-6-F-Trp-NH₂ (SEQ NO:92); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-3-CH₃ O-Trp-NH₂ (SEQ NO:93); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-N-Methyl-Trp-NH₂ (SEQ NO:94); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-1-Methyl-Trp-NH₂ (SEQ NO:95); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-4-Methyl-Trp-NH₂ (SEQ NO:96); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Methyl-Trp-NH₂ (SEQ NO:97); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-6-Methyl-Trp-NH₂ (SEQ NO:98); 4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-5-Hydroxy-Trp-NH₂ (SEQ NO:99); and, pharmaceutically acceptable salts thereof.
 12. A pentapeptide composition or salt thereof, selected from the group consisting of:4-F-Phe-isonipecotic acid-Arg-Gly-Trp-NH₂ (4-pyridinecarboxylic acid) (SEQ NO:100); 4-F-Phe-2-Carboxy-Azetidine-Arg-Gly-Trp-NH₂ (SEQ NO:101); 4-F-Phe-2-carboxy-Aziridine-Arg-Gly-Trp-NH₂ (SEQ NO:103); 4-F-Phe-3-Carboxy-1,4,5,6-Tetrahydropyridine-Arg-Gly-Trp-NH₂ (SEQ NO:105); 4-F-Phe-2-Carboxypyrrole-Arg-Gly-Trp-NH₂ (SEQ NO:106); and, pharmaceutically acceptable salts thereof.
 13. A pentapeptide composition or salt thereof, comprising a general formula (13):

    R.sup.1 -Phe-AA.sup.1 -Arg-Gly-Trp-NH.sub.2 (SEQ ID NO:122)(13)

wherein R¹ represents a halogen atom and AA¹ represents an amino acid selected from the group consisting of 1-amino-1-carboxycyclopentane and 1-amino-1-carboxycyclopropane.
 14. The pentapeptide of claim 13 selected from the group consisting of:4-F-Phe-1-Amino-1-Carboxycyclopentane-Arg-Gly-Trp-NH₂ (SEQ NO:102); 4-F-Phe-1-Amino-1-Carboxy-Cyclopropane-Arg-Gly-Trp-NH₂ (SEQ NO:104); and, pharmaceutically acceptable salts thereof.
 15. A pentapeptide composition consisting essentially of at least one of:4-F-Phe-3,4-Dehydro-Pro-Arg-Sar-Trp-NH₂ (SEQ NO:110); and, pharmaceutically acceptable salts thereof.
 16. A hexapeptide composition or salt thereof, comprising a general formula (10):

    R.sup.1 -AA.sup.1 -R.sup.2 -Pro.sup.1 -AA.sup.2 -AA.sup.4 -Gly-AA.sup.3 -R (SEQ ID NO:128)                                           (10)

where Pro¹ represents the amino acid dehydro-Pro; AA¹ represents the amino acid Phe; AA² represents the amino acid Arg; AA³ represents the amino acid Trp; AA⁴ represents the amino acid Gly; R is selected from the group consisting of a carboxyl group, a hydroxyalkyl group, a carbamyl group, an alkylcarbamyl group, and an alkoxycarbonyl group; and, R¹ and R² each independently are selected from the group consisting of a hydrogen atom, a lower alkyl group, a fluorine atom a chlorine atom, a cis-4-OH- group, a trans-4-OH- group, a sulphydryl group, an alkylamino group and a dialkylamino group.
 17. The hexapeptide of claim 16 selected from the group consisting of:4-F-Phe-3,4-Dehydro-Pro-Arg-Gly-Gly-Trp-NH₂ (SEQ NO:80); and, pharmaceutically acceptable salts thereof. 